Added support for config-file-provider plugin (# 476)

[srempfer]

#476

@ndeloof: I'm new in Jenkins plugin contribution, so please let me know what do think about the code.
Regrads Stefan

[oleg-nenashev]

IMHO the fix should be done on the Config File Provider Plugin side. JCasC is in the RC state, so nothing blocks from making fixes in plugins directly

[ndeloof]

I agree with @oleg-nenashev that this should be proposed as an optional extension to config-file-provider, as we would like to move all custom configurators to target plugins. Also, doing so you can introduce in GlobalConfigFiles the missing setConfigs setter that make it required to implement custom code, and will just need to declare a RootConfigurator.

[srempfer]

Just created a JIRA ticket (JENKINS-53247) - will try to do the compatibility changes there

[ndeloof]

right.
And doing so you might not even need a custom RootElementConfigurator assuming I get #480 merged

[HerrmannHinz]

yay! super! just in time =)

[ndeloof]

closing this with preference to a PR on config-file-provider plugin