[WIP] Handling unloading of diagnostics by service

[stonier]

First iteration on attempting to solve the problem highlighted by #50.

• Stores the bond, analyzer into a vector of pairs (previously just the bond)
• Toggles loaded<->unloaded whenever a service call to add_diagnostics is made depending on if it is not yet loaded or already loaded.

Kind of aiming for a minimum delta here. I would say tackling this more properly should require the addition of a separate remove_diagnostics service with its own type (or at least a dual-purpose name for the diagnostics_msgs/AddDiagnostics srv).

If this is required, I can push this PR in that direction.

Just a reminder for us, will also need a cherry-pick across to the master branch.

[AlexReimann]

Still working on this?

[amilcarlucas]

This needs a rebase

[AlexReimann]

Fyi: Myself doesn't plan to be working on this anymore

[g-gemignani]

Closing due to inactivity