Also disables occurrences highlights & the line highlight for the review
mode.

Closes #44307

Closes #44298

This also makes the IDE generally available

But first, rewrite the performance bar in Vue:

1. Remove the peek-host gem and replace it with existing code. This also allows
   us to include the host in the JSON response, rather than in the page HTML.
2. Leave the line profiler parts as here-be-dragons: nicer would be a separate
   endpoint for these, so we could use them on Ajax requests too.
3. The performance bar is too fiddly to rewrite right now, so apply the same
   logic to that.

Then, add features! All requests made through Axios are able to be tracked. To
keep a lid on memory usage, only the first two requests for a given URL are
tracked, though. Each request that's tracked has the same data as the initial
page load, with the exception of the performance bar and the line profiler, as
explained above.

removed pointless test & changed some deployment tests to make more sense
added in v-tooltip

[ci skip]

added spec for polling

Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/4281

Closes #33264