Dev Validate: Update with the ability to run remote/multiple validations.

[mike-winberry]

Is your feature request related to a problem? Please describe.

Should the lula dev validate command be updated to allow for remote or multiple validation files to be run without a component definition.

Describe the solution you'd like

• Given file or url with multiple validations
• When lula dev validate is run
• Then the external validation or multiple validations are run

Additional context

• Is this useful?
• depends on feat: #298 Add the ability to pull validations from external sources (currently only backmatter) #357

[brandtkeller]

Evaluate uses cases further - decompose issue (Add here later) opinionates the separation of validations into single validation files.