mock improvements

[johncowen]

Description

Our mocks have pretty much stayed using the hurriedly built mocking framework from when we started re-architecting the application, they also started off with a set of mocks from the old-style application that were probably old.

There are several things we could do to make things easier/improve our mocks, some are more urgent than others, so feel free to make sub issues for the following if its easier.

• Fill out more new style mocks/entities. There are hardly any mocks for new style policies (for example I think only MeshFaultInjection as a full set of mocks), we should fill out at least a couple more.
• Would be nice to continue https://github.com/kumahq/kuma-gui/issues/2001
• The fs.ts file that the mocks use should ideally be auto generated from the file system. Its beginning to get a little out of hand manually editing these files.
• Mocks should live in @/app/kuma/ (in a @/app/kuma/mocks folder or similar)
• We should 'deprecate' old style policies resources. This might mean just splitting them into separate variables for easy removal at a later date.
• I think I've mentioned a refactor/cleanup of the code fake-api is probably needed, but this is the least priority. It all works fine, just its one of those "I wish this was better organized" whenever i need to go into the code there.