WIP: Add ability to upgrade GitLab Runnner application (frontend)

What does this MR do?

This MR adds the ability to upgrade the GitLab runner from the frontend.

Also adds the functionality to display runner version number on the frontend.

Successful upgrade

Upgrade available -> Upgrade successful

To simulate an "Upgrade available" state, the following commands can be executed:

Open rails console: bundle exec rails console

In rails console execute the following:

1. cluster = Clusters::Cluster.find <id> Note: <id> can be found in the browser url when navigating to the cluster
2. runner = cluster.application_runner
3. runner.update!(version: '0.0.0')

The runner on the specified cluster should now be in the update_available state, and should display the Upgrade button

Upgrade failure

Upgrade failure -> Upgrade successful

To simulate an "Upgrade failure" state, the following commands can be executed:

Open rails console: bundle exec rails console

In rails console execute the following:

1. cluster = Clusters::Cluster.find <id> Note: <id> can be found in the browser url when navigating to the cluster
2. runner = cluster.application_runner
3. runner.update!(status: 6)

The runner on the specified cluster should now be in the update_errored state, and should display the Retry upgrade button

What are the relevant issue numbers?

Closes #49384 (closed)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the style guides