Add button to create a Release through the UI

What does this MR do?

Adds a "New release" button to the Releases page.

This button will redirect the user to the New Tag page, where a user can create a new Tag and optionally create a new associated Release. The help text on this page has also been made more prominent to make it clear how to go about creating a new Release.

UX specs

UX specs can be seen in the Design tab of #32812 (closed): #32812 (designs) (create-release-form.png)

Screenshots

When a project has no Releases

Note: the text "Read more" has been update to "More information". See !24516 (comment 300655263).

When a project has at least one Release

New Tag page

Feature flag

This change is not behind a feature flag.

Closes #32812 (closed)