Changing wording to "Delete" when referring to removing a branch

Description

When creating a merge request, we have the option Remove source branch when merge request is accepted.

We do have the same message in the MR screen:

Finally, on the branches screen, we have the following action: Delete branches.

Finally, the icon to delete a branch is a trash, symbolizing the deletion, not the removal, per se.

Design

• Change all wording in regard to "removing a branch" to be Delete.
• This includes all the places mentioned here