* core: allow pause/un-pause of eval broker on region leader.
* agent: add ability to pause eval broker via scheduler config.
* cli: add operator scheduler commands to interact with config.
* api: add ability to pause eval broker via scheduler config
* e2e: add operator scheduler test for eval broker pause.
* docs: include new opertor scheduler CLI and pause eval API info.
This is a followup to running tests in serial in CI.
Since the API package cannot import anything outside of api/,
copy the ci.Parallel function into api/internal/testutil, and
have api tests use that.
* Divest api/ package of deps elsewhere in the nomad repo.
This will allow making api/ a module without then pulling in the
external repo, leading to a package name conflict.
This required some migration of tests to an apitests/ folder (can be
moved anywhere as it has no deps on it). It also required some
duplication of code, notably some test helpers from api/ -> apitests/
and part (but not all) of testutil/ -> api/testutil/.
Once there's more separation and an e.g. sdk/ folder those can be
removed in favor of a dep on the sdk/ folder, provided the sdk/ folder
doesn't depend on api/ or /.
* Also remove consul dep from api/ package
* Fix stupid linters
* Some restructuring
