Zoom meetings model and migrations

What does this MR do?

This MR creates a new table zoom_meetings which persists Zoom meetings, its association to an issue and its metadata (currently only the URL). Although technically not required we also associate to project (via project_id) to avoid table joins.

In this MR we assume that per issue only Zoom meeting at a time can have status added. Hence, the database uniqueness constraint.

A follow-up MR could make use of this model in Issues::ZoomLinkService to replaces its current storage like adding and removing.

Alternative solutions

Alternatively, instead of changing it status we could delete a Zoom meeting from the database after we've removed it from the issue via /remove_zoom.

We would store less data but would lose potential information for later use.

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation created/updated or follow-up review issue created
• [-] Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team

Part of #33042 (closed)