XLIFF format customization

### Describe the problem

Once file formats are customizable (see https://github.com/WeblateOrg/weblate/issues/1897), the following should be available for XLIFF:

* Closing tags behavior (currently in XML add-on)
* Whitespace handling: standard (follow xml:space) / always preserve / always normalize
* Tags handling (currently handled by two formats)

### Describe the solution you'd like

Additional form should be available when choosing file format.

### Describe alternatives you've considered

Current situation kind of works (choosing format variants, installing add-ons, ...), but does not provide configuration where people expect it.

### Screenshots

_No response_

### Additional context

Depends on https://github.com/WeblateOrg/weblate/issues/1897