Use unit absolute URLs for translating

### Describe the problem

Users often share link to a current search, what is not really a good way to share link to a unit.

### Describe the solution you'd like

* The actual translation URLs will include unit ID (via `get_url_path`)
* Search will navigate through a (session cached) list of matches
* If the current unit is not part of the search, a warning will be shown, but the user will still stay on that unit

### Describe alternatives you've considered

_No response_

### Screenshots

_No response_

### Additional context

Reasons for this change:

* Saving will always work even if some changes happen (see https://github.com/WeblateOrg/weblate/discussions/11605).
* Users will be able to share current unit URL directly without need for permalink button.