[translations] ./manage rename shell functions to integrate weblate

Functions implemented to run *Weblate* workflows should use prefix 'weblate.':

- babel.setup.translations.worktree --> weblate.translations.worktree

  Create git worktree ${TRANSLATIONS_WORKTREE} and checkout branch
  'translations' from Weblate's counterpart (weblate) of the SearXNG
   (origin)::

       remote weblate https://weblate.bubu1.eu/git/searxng/searxng/



- babel.weblate.to.translations     --> weblate.to.translations

  Update 'translations' branch of SearXNG (origin) with last additions from
  Weblate.

- babel.translations.to.master      --> weblate.translations.commit

  Update 'translations' branch of SearXNG (origin) with last additions from
  Weblate.  Copy the changes to the master branch, compile translations and
  create a commit in the local branch (master)

- babel.master.to.translations      --> weblate.push.translations

  Push *translation changes* from SearXNG (origin) to Weblate's
  counterpart (weblate).

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>