Merge branch 'jfarmiloe-alpha-beta-support-def-docs' into 'master'

New page with alpha/beta support definitions from handbook

See merge request gitlab-org/gitlab!67718

doc/policy/alpha-beta-support.md

+---
+stage: Enablement
+group: Distribution
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
+---
+
+# Support for Alpha, Beta, and Generally Available Features **(PREMIUM)**
+
+Some GitLab features are released as [Alpha or Beta versions](https://about.gitlab.com/support/statement-of-support.html#alpha--beta-features) which are not fully supported. All other features are considered to be Generally Available (GA).
+
+## Alpha Features
+
+Characteristics of alpha features:
+
+- Not ready for production use.
+- Unstable and can cause performance and stability issues.
+- Configuration and dependencies are likely to change.
+- Features and functions may be removed.
+- Data loss can occur (be that through bugs or updates).
+
+Support is **not** provided for Alpha features and issues with them should be opened in the [GitLab issue tracker](https://gitlab.com/gitlab-org/gitlab/issues).
+
+## Beta Features
+
+Characteristics of beta features:
+
+- Not ready for production use.
+- Unstable and can cause performance and stability issues.
+- Configuration and dependencies are not likely to change.
+- Features and functions are not likely to change.
+- Data loss is not likely.
+
+Your Support Contract provides **best-efforts** support for Beta features, with the expectation that issues will require extra time and assistance from development to troubleshoot.
+
+## Generally Available (GA)
+
+Generally Available features means that they passed the [Production Readiness Review](https://gitlab.com/gitlab-com/gl-infra/readiness/-/blob/master/.gitlab/issue_templates/production_readiness.md) for GitLab.com, and are:
+
+- Ready for production use at any scale.
+- Fully documented and supported.