* Handle push rejections and push out-of-date in branch creation and
file upload.
* Remove the duplicated sanitize from services/pull/merge
* Move the errors Err(Merge)PushOutOfDate and ErrPushRejected to
modules/git
* Handle errors better in the upload file dialogs

Fix #10460

Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: guillep2k <18600385+guillep2k@users.noreply.github.com>

Move more general repository functions out of models/repo.go

* Add require signed commit for protected branch

* Fix fmt

* Make editor show if they will be signed

* bugfix

* Add basic merge check and better information for CRUD

* linting comment

* Add descriptors to merge signing

* Slight refactor

* Slight improvement to appearances

* Handle Merge API

* manage CRUD API

* Move error to error.go

* Remove fix to delete.go

* prep for merge

* need to tolerate \r\n in message

* check protected branch before trying to load it

* Apply suggestions from code review

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

* fix commit-reader

Co-authored-by: guillep2k <18600385+guillep2k@users.noreply.github.com>

* Move wiki related funtions from models to services/wiki