Change manifest locations, repos and branches based on major version

[jhugman]

Fixes EXP-4162.

Following the moves of firefox-ios and focus-ios, this PR adds version awareness to the manifest locations, repositories, and branch format.

All of these things have varied independently of one another.

Testing of this PR has been done only by visual inspection, with scripts like this:

min_version=108
app=focus_ios
experiment=https://experimenter.services.mozilla.com/nimbus/viewpoint-android-dec-2023
for n in $(seq $min_version 122); do
    nimbus-cli --app focus_ios --channel release validate --version $n $experiment 
done

This is due to no single experiment is valid across all versions of an app. This will change once we can feed the calculated URL (or equivalent) to the FML command line. To limit the scope of the PR this is not done here.

A speedy landing will unblock QA who will be unexpectedly blocked from testing firefox and focus experiments on iOS today.

Pull Request checklist

• Breaking changes: This PR follows our breaking change policy
  • This PR follows the breaking change policy:
    • This PR has no breaking API changes, or
    • There are corresponding PRs for our consumer applications that resolve the breaking changes and have been approved
• Quality: This PR builds and tests run cleanly
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• Tests: This PR includes thorough tests or an explanation of why it does not
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  • Any breaking changes to Swift or Kotlin binding APIs are noted explicitly
• Dependencies: This PR follows our dependency management guidelines
  • Any new dependencies are accompanied by a summary of the due dilligence applied in selecting them.

Branch builds: add [firefox-android: branch-name] to the PR title.

[brennie]

This comment is wrong.

[brennie]

We should consider using a crate like semver long term.