[FIXED JENKINS-50561] Add rateLimitBuilds symbol

[abayer]

JENKINS-50561

I wanted to avoid "throttle" in the symbol, since that's already a
thing over in Throttle Concurrent Builds, and "throttle" means
something different there than it does here.

[jglick]

Sounds right, but do you have some integration test showing it being used successfully, e.g. in a Declarative options section? I ask because this is not your usual job property—it was originally designed to be added via branch property, i.e., in multibranch folder configuration rather than in Jenkinsfile. (In fact I think it was originally created for freestyle multibranch.)

[abayer]

Nope - good point. I'll work on that.

[abayer]

@jglick Done - jenkinsci/pipeline-model-definition-plugin#284

[abayer]

Debating whether RateLimitBranchProperty.Throttle should have a symbol too - honestly, I don't think so, if for no other reason than I can't think of a good name, and the rateLimitBuilds(throttle: [count: 1, durationName: 'day', userBoost: false]) syntax is Good Enough.