Oauth multi resource support

[MarcialRosales]

Proposed Changes

see https://github.com/rabbitmq/rabbitmq-server/issues/7746

Types of Changes

What types of changes does your code introduce to this project? Put an x in the boxes that apply

• [ ] Bug fix (non-breaking change which fixes issue #NNNN)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause an observable behavior change in existing systems)
• [ ] Documentation improvements (corrections, new content, etc)
• [ ] Cosmetic change (whitespace, formatting, etc)
• [ ] Build system and/or CI

Tasks

• [x] Use keycloak for selenium tests because it is easier to configure TLS for jwks
• [x] Clear oidc client library's state either just before redirecting the user to the authorization server or when an error occurs
• [x] Take into account initiated_login_type . Atm it assumes it is sp_initiated from the selection box
• [x] Include basic authentication to the initial page if enabled
• [x] Rename all selenium's .env files to env to facilitate merging in some editing tools
• [x] Refactored all components' start_ and init_ functions out from suite_template
• [x] Write documentation : https://github.com/rabbitmq/rabbitmq-website/pull/1710
• [x] Replace rabbitmqctl command add_uaa_key with add_signing_key. Keep àdd_uaa_key` around for at least a release or two. Announce in release notes that it will be soon deprecated. The command's description also says that it is deprecated although it is fully functional.