Improve English locale source and update all files

The MR fixes various small typos in the English source version.

What I did (each step with a dedicated commit)

1. I added *.swp exention to a new editor section in .gitignore.
2. Move the email in the pt_BR locale files from Report-Msgid-Bugs-To to the new Language-Team field.
3. Run makemessages to update locale files, e.g. line number changes, POT files update.
4. Fix small things in various files (double space, missing point, typos, ellipsis).
5. Fix typo in keyring/models.py and update migrations accordingly.

Closes: #155 (closed)