User Defined Action Concurrency Limits

[bdoyle0182]

Description

Gives users the ability to configure action concurrency limits on their action with respect to their namespace concurrency limit. This finally allows users to be able to configure some level of fairness within their namespace. See POEM 4 for considerations and design. Once the POEM is approved, I will add documentation, tests, and feedback to this PR.

Related issue and scope

• [ ] I opened an issue to propose and discuss this change (#????)

My changes affect the following components

• [X] API
• [X] Controller
• [ ] Message Bus (e.g., Kafka)
• [ ] Loadbalancer
• [X] Scheduler
• [ ] Invoker
• [ ] Intrinsic actions (e.g., sequences, conductors)
• [ ] Data stores (e.g., CouchDB)
• [X] Tests
• [ ] Deployment
• [ ] CLI
• [ ] General tooling
• [X] Documentation

Types of changes

• [ ] Bug fix (generally a non-breaking change which closes an issue).
• [X] Enhancement or new feature (adds new functionality).
• [ ] Breaking change (a bug fix or enhancement which changes existing behavior).

Checklist:

• [X] I signed an Apache CLA.
• [X] I reviewed the style guides and followed the recommendations (Travis CI will check :).
• [X] I added tests to cover my changes.
• [X] My changes require further changes to the documentation.
• [X] I updated the documentation where necessary.