Dotcom and Apps Nav Tool

At the moment every time a change is required, CP makes a request to both the WebX and Apps teams to create and merge separate PRs. In some cases the change is temporary, perhaps for a specific event, so subsequent requests then need to be made to change it back. It would be better if CP had a tool to do this themselves. This would be easier, faster, and wouldn't place engineers on the critical path for making changes.

Initial work to build the UI for the apps part of this can be seen in #14815. There are some further steps required to complete this, and extend it to dotcom as well.