Add support for Debian 11 ("bullseye")

[rbhanda]

This issue is created to track progress for the work to enable Debian 11 support for .NET Core 3.1 and .NET 5.0.

• Debian 11 ("bullseye")
• Debian 11 ("bullseye") release announcement
• Debian releases
• .NET 6 Bullseye support

Product and Test updates

• [All teams] Do a compatibility check for the product with the new OS
• [CoreCLR/CoreFX] Runtime / RID Support update
• [Infra] Ensure that the correct Docker images used by teams are built in the dotnet-buildtools-prereqs (if applicable)
• [Infra] Replace docker tags used in builds across repos and branches
• [CLI team] Update CI legs to latest updated Dockerfile
• [All teams] Update test infrastructure to support the new version
• Acquisition] Add support within nightly repos
• Acquisition] Deploy to master (GA) during next patch release cycle

Release team:

• Notify .NET Core teams regarding new OS release
• Follow up with infra and add feed for new OS release to packages.microsoft.com
• Update release manifest files
• Create new Docker files to test the new OS
• Update the supported OS content on GitHub and marketing sites.

Document updates:

• Add OS prerequisites to the dependencies document
• Update distro install page

[ashnaga]

Supported, resolving this one