[Feature]: Consider changing default NuGetGallery repo branch to dev

[joelverhagen]

Related Problem

User request: #9987 (comment)

The Elevator Pitch

Currently the default branch of NuGet/NuGetGallery is main branch. We can consider changing the dev branch to be the default.

Pros:

• Easier contribution because we expect PRs to be based against dev by default
  • Definitely useful for community contributions so that the default matches the contributing guide (https://github.com/NuGet/NuGetGallery/blob/main/CONTRIBUTING.md#getting-started)

Cons:

• Default git clone or Download ZIP will a revision that may never be deployed to PROD
• main has a higher chance of being stable because it is what we deploy to PROD and hotfix against

Additional Context and Details

No response

[loic-sharma]

A potential alternative:

1. Rename main to stable
2. Rename dev to main
3. Make the new main (old dev) the default branch

This has the similar pros/cons as above, plus:

➕ I think this is what we'd do if we had a clean slate
➕ We'd get to keep the main default branch name
➖ It's more work as we need to update deployment scripts as well