As LRDE is being renamed LRE, gitlab is one of the first URL to
migrate.  The old URL is still supported, but we want to only use the
new one eventually.

* .dir-locals.el, .gitlab-ci.yml, HACKING, NEWS, doc/org/concepts.org,
doc/org/install.org, doc/org/setup.org, elisp/Makefile.am,
elisp/hoa-mode.el, tests/ltsmin/README: Update to the new gitlab URL.