Gerrit-integration: provide a way to add topic and/or hashtags (ignores branch%topic=foo in push-branch)

### Describe the problem

Pushing to gerrit will likely trigger CI actions and depending on the project size those can be quite expensive, and usually translation updates won't be tested or don't need to be tested with every update to a patch/once when merged is enough.

Using a topic or keywords can be used as a generic way to skip CI actions or phases without having the need to add the weblate committer and other bot accounts into the CI rules

### Describe the solution you'd like

simplest way would be if weblate would pass the push-branch, using branchname%topic=topiclabel would be the way to add a topic to a change while pushing to gerrit
https://gerrit-review.googlesource.com/Documentation/intro-user.html#topics

similarly keywords/hashtags can be added using the same way

### Describe alternatives you've considered

alternatives would be different input options allowing to specify topic (single value) and/or hashtags (can be multi-value, however hashtags aren't part of e.g. jenkins gerrit-trigger filters, so less useful for controlling CI in this case)

### Screenshots

_No response_

### Additional context

_No response_