Move warden and team registration to another repo and include as git submodule

Problem/opportunity:

• As we expand write access to the site to include more community support and process around onboarding new wardens, permissions get messier.
• Having a 100% public warden application review process is different from how we handle other applications and may lead to awkward scenarios
• Notifications of warden application activity adds a lot of noise to the website repo and website dev activity adds a lot of noise to the application review process

Desired outcome

• Warden application reviewers have robust access to be able to review and merge applications without also having full write access to the website and other C4 data
• Warden application reviewers are able to use GitHub to openly review and discuss applications that they are on the fence about.

Proposed solution:

• separate private repo for warden applications and data (ie github.com/code-423n4/wardens)
• import as submodule into site repo
• use github actions to trigger website deploys when there is a new merge in wardens repo
• create warden application review GitHub team to manage permissions
• use private GitHub PR discussions to review warden applications

Start by reviewing the proposed private wardens repository, Git submodule integration, GitHub Actions deployment trigger, and GitHub team permissions described in the issue. Done means applications and review discussions are separated from the website repository while approved changes still trigger website deploys.