First cut to the new, split into multiple, ci runner

This is the very first version of the new ci runner that
splits jobs into smaller modules, available for jobs to
orchestrate them.

This includes a working version of the phpunit job, to
be used as a reference for the migration of the behat
tests and also to create some new job to experiment
with the flexibility of the system.

Note that this is not production-ready yet, just work
in progress to go trying stuff. Once the system is stable
and tested enough we'll go advancing with the implementation plan.

For more information and updates, this is the issue to follow:

#111

runner/master/jobtypes/phpunit/phpunit.sh

@@ -0,0 +1,168 @@
+#!/usr/bin/env bash
+#
+# This file is part of the Moodle Continuous Integration Project.
+#
+# Moodle is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Moodle is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Moodle.  If not, see <https://www.gnu.org/licenses/>.
+
+# PHPUnit job type functions.
+
+# PHPUnit needed variables to go to the env file.
+function phpunit_to_env_file() {
+    local env=(
+        DBTYPE
+        DBTAG
+        DBHOST
+        DBNAME
+        DBUSER
+        DBPASS
+        DBCOLLATION
+        DBREPLICAS
+        DBHOST_DBREPLICA
+
+        BBBMOCKURL
+        MATRIXMOCKURL
+
+        REDISTESTNAME
+        MEMCACHED1TESTURL
+        MEMCACHED2TESTURL
+        MONGODBTESTURL
+
+        EXTTESTURL
+        LDAPTESTURL
+        SOLRTESTNAME
+
+        MLBACKENDTESTNAME
+    )
+    echo "${env[@]}"
+}
+
+# PHPUnit information to be added to the summary.
+function phpunit_to_summary() {
+    echo "== Moodle branch (version.php): ${MOODLE_BRANCH}"
+    echo "== PHP version: ${PHP_VERSION}"
+    echo "== DBTYPE: ${DBTYPE}"
+    echo "== DBTAG: ${DBTAG}"
+    echo "== DBREPLICAS: ${DBREPLICAS}"
+    echo "== MLBACKEND_PYTHON_VERSION: ${MLBACKEND_PYTHON_VERSION}"
+    echo "== RUNCOUNT: ${RUNCOUNT}"
+    echo "== PHPUNIT_FILTER: ${PHPUNIT_FILTER}"
+    echo "== PHPUNIT_TESTSUITE: ${PHPUNIT_TESTSUITE}"
+}
+
+# This job type defines the following env variables
+function phpunit_env() {
+    env=(
+        RUNCOUNT
+        PHPUNIT_FILTER
+        PHPUNIT_TESTSUITE
+        EXITCODE
+    )
+    echo "${env[@]}"
+}
+
+# PHPUnit needed modules. Note that the order is important.
+function phpunit_modules() {
+    local modules=(
+        env
+        summary
+        docker
+        docker-logs
+        git
+        plugins
+        docker-database
+        docker-mocks
+        docker-caches
+        docker-exttests
+        docker-ldap
+        docker-solr
+        docker-mlbackend
+        docker-php
+        moodle-core-copy
+        docker-healthy
+        docker-summary
+    )
+    echo "${modules[@]}"
+}
+
+# PHPUnit job type checks.
+function phpunit_check() {
+    # Check all module dependencies.
+    verify_modules $(phpunit_modules)
+
+    # These env variables must be set for the job to work.
+    verify_env UUID ENVIROPATH WEBSERVER
+}
+
+# PHPUnit job type init.
+function phpunit_config() {
+    # Apply some defaults.
+    RUNCOUNT="${RUNCOUNT:-1}"
+    PHPUNIT_FILTER="${PHPUNIT_FILTER:-}"
+    PHPUNIT_TESTSUITE="${PHPUNIT_TESTSUITE:-}"
+    EXITCODE=0
+}
+
+# PHPUnit job type setup.
+function phpunit_setup() {
+    # Init the PHPUnit site.
+    echo
+    echo ">>> startsection Initialising PHPUnit environment at $(date)<<<"
+    echo "============================================================================"
+    docker exec -t -u www-data "${WEBSERVER}" \
+        php admin/tool/phpunit/cli/init.php \
+            --force
+    echo "============================================================================"
+    echo ">>> stopsection <<<"
+}
+
+# PHPUnit job type run.
+function phpunit_run() {
+    # Run the job type.
+    echo
+    if [[ RUNCOUNT -gt 1 ]]; then
+        echo ">>> startsection Starting ${RUNCOUNT} PHPUnit runs at $(date) <<<"
+    else
+        echo ">>> startsection Starting PHPUnit run at $(date) <<<"
+    fi
+    echo "============================================================================"
+    # Build the complete command
+    local cmd=(
+        php vendor/bin/phpunit
+        --disallow-test-output
+        --fail-on-risky
+        --log-junit /shared/log.junit
+        --verbose
+    )
+    if [[ -n "${PHPUNIT_FILTER}" ]]; then
+        cmd+=(--filter "${PHPUNIT_FILTER}")
+    fi
+    if [[ -n "${PHPUNIT_TESTSUITE}" ]]; then
+        cmd+=(--testsuite "${PHPUNIT_TESTSUITE}")
+    fi
+
+    echo "Running: ${cmd[*]}"
+
+    # Run the command RUNCOUNT times.
+    local iter=1
+    while [[ ${iter} -le ${RUNCOUNT} ]]; do
+        echo
+        echo ">>> PHPUnit run ${iter} at $(date) <<<"
+        docker exec -t "${WEBSERVER}" "${cmd[@]}"
+        EXITCODE=$((EXITCODE + $?))
+        iter=$((iter+1))
+    done
+
+    echo "============================================================================"
+    echo ">>> stopsection <<<"
+}