add bearer_token_format and idp_access_token_allowed_audiences

[calebdoxsey]

Summary

Add the bearer_token_format and idp_access_token_allowed_audiences global and route-level options.

Related issues

• ENG-2020

Checklist

• reference any related issues
• updated docs
• updated unit tests
• updated UPGRADING.md
• add appropriate tag (improvement / bug / etc)
• ready for review

[backport-actions-token]

The backport to 0-28-exp failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-0-28-exp 0-28-exp
# Navigate to the new working tree
cd .worktrees/backport-0-28-exp
# Create a new branch
git switch --create backport-1103-to-0-28-exp
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick --mainline 1 e6e6c31289fd77848590108cceeb0798615dd229
# Push it to GitHub
git push --set-upstream origin backport-1103-to-0-28-exp
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-0-28-exp

Then, create a pull request where the base branch is 0-28-exp and the compare/head branch is backport-1103-to-0-28-exp.