feat: create oauth2 auth trigger, integrate it with rabbitmq scaler

[KyriosGN0]

Provide a description of what has been changed

This PR add a new OAuth2 spec to to TriggerAuth crd, this spec will generate an access token that is returned to the scaler.
This PR also integrates this new spec to RabbitMQ scaler (currently only for http connection)
this allows people who use RabbitMQ with OAuth to use a timed access token instead of username/password

Checklist

• When introducing a new scaler, I agree with the scaling governance policy
• I have verified that my change is according to the deprecations & breaking changes policy
• Tests have been added (if applicable)
• Ensure make generate-scalers-schema has been run to update any outdated generated files
• Changelog has been updated and is aligned with our changelog requirements, only when the change impacts end users
• A PR is opened to update our Helm chart (repo) (if applicable, ie. when deployment manifests are modified)
• A PR is opened to update the documentation on (repo) (if applicable)
• Commits are signed with Developer Certificate of Origin (DCO - learn more)

Fixes #

Relates to #7379

[github-actions]

Thank you for your contribution! 🙏

Please understand that we will do our best to review your PR and give you feedback as soon as possible, but please bear with us if it takes a little longer as expected.

While you are waiting, make sure to:

• Add an entry in our changelog in alphabetical order and link related issue
• Update the documentation, if needed
• Add unit & e2e tests for your changes
• GitHub checks are passing
• Is the DCO check failing? Here is how you can fix DCO issues

Once the initial tests are successful, a KEDA member will ensure that the e2e tests are run. Once the e2e tests have been successfully completed, the PR may be merged at a later date. Please be patient.

Learn more about our contribution guide.

[snyk-io]

✅ Snyk checks have passed. No issues have been found so far.

Status	Scanner	Critical	High	Medium	Low	Total (0)
✅	Open Source Security	0	0	0	0	0 issues

💻 Catch issues earlier using the plugins for VS Code, JetBrains IDEs, Visual Studio, and Eclipse.

[zroubalik]

Could you please also open docs PR (documenting both new TriggerAuth config and RabbitMQ)?

[zroubalik]

Could you please omit these non related changes from the PR?