Add support for new agent tasks REST API

[stevehipwell]

GitHub announced a new agent tasks REST API. We should support it.

[danyalahmed1995]

Good idea. I can take a look at adding support for this. I’ll follow the existing service/test patterns and keep the initial PR scoped to the documented agent tasks endpoints.

[gmlewis]

Thank you, @danyalahmed1995!
CONTRIBUTING.md has some helpful information in it, of particular note is "step 4". 😄

[danyalahmed1995]

@gmlewis Opened #4225 with support for the documented Agent Tasks endpoints. Thanks for the pointer to CONTRIBUTING.md, the validation flow there was helpful 😅.