* Add API types for CircleCI joining
* Add validation for CircleCI configuration
* Add JoinMethodCircleCI across codebase
* Add token validator and token source for circleci
* Update join methods RFD
* Add CircleCI token source to register.go
* Add serverside support for circleci joining
* Add test for TokenSource
* Add success case for token validation test
* Add expired test case
* Add test case for token from another org
* Test RegisterWithToken for CircleCI
* Refactor GitHub RegisterUsingToken tests
* Refactor CircleCI RegisterUsingToken tests
* Add tests for ProvisionTokenSpecV2
* Appease linters
* Go Imports files
* Fix failing test for msising IDtoken
* Update lib/auth/join_circleci.go
Co-authored-by: Zac Bergquist <zac.bergquist@goteleport.com>
* Move test server cleanup closer to initialisation
* Fix weird import reordering
* Include unexpected type in error message
* Simplify boolean algebra :)
Co-authored-by: Zac Bergquist <zac.bergquist@goteleport.com>