Add support for Service Event Rules

[mrzacarias]

Adding support for Service Event Rules. API reference:
List Service's Event Rules
Get an Event Rule from a Service
Delete an Event Rule from a Service
Create an Event Rule on a Service
Update an Event Rule on a Service

Some other changes:

• Added the "suspend" rule action to keep the rule payload up to date with the API.
• Adding Service Rule List and Service Rule Show CLI commands
• Stubbing other possible Service Rule CLI commands

Edit: Forgot to mention, but I got trouble making the CLI logic work without changing the references to our own fork, so I commented the code for now. As soon as we merge this PR, we can have the implemented CLI commands working by uncommenting this code.

[theckman]

@mrzacarias I'll get to reviewing this in the coming days, once I finish a set of PRs I am raising against the repo. Thank you for the contribution.

[theckman]

Hey there, I've some other PRs in flight that are making some fairly large changes to the internals of this package. Unfortunately, your PR is overlapping with some of those and so I've requested changes to have this code align more closely to what changes I am making there. That includes things like accepting a context.Context, no longer returning a *http.Response from API methods, and only using pointer types where they make sense for semantic reasons.

Please let me know if you have any questions about this feedback. 👍

[mrzacarias]

@theckman Thanks for carefully reviewing this PR :)

[theckman]

@mrzacarias I think I may have found two more minor things that didn't dawn on me before. Since changing the types would be a breaking change after release, I want to make sure we get this right.

Happy to be wrong with my requested changes, if so give me a shout.

[theckman]

@mrzacarias thank you for the contribution. There are still a few changes in-flight for v1.4.0, and so it make take a few more days (maybe weeks) until those get buttoned up. Once they do you'll be part of that version.

Thanks again!