- added directions on using the ./tools/browser/sign-tag script
- removed some extraneous checkboxes
- made Run: directives consistent
- fixed some typos

Update pkg_revision to force rebuild of linux-packages. Having
var/browser_release_date being in the past should solve the
reproducibility problem of the deb file.

The patch for #41122 was backported to `maint-13.0`, so we need to
update the stable release prep gitlab issue templates.

Update the release preparations for the new changelog script arguments
and also to fix some steps that were not correct anymore.

Update Mullvad Browser release prep templates to include downstream package notification/maintenance