[ADD] base: add Tagalog language

This is the first move to replace Filipino by Tagalog language

Using Filipino (code fil_PH) is problematic as conflicts with Finnish
(code fi_FI) and users having their browser in Finnish were redirected
to the Filipino version of the website (cf discussion at opw-2172710).

This problem was also raised in other softwares like in the below
discssion in Mozilla L10N groups
https://groups.google.com/forum/#!topic/mozilla.dev.l10n/TW2qYyDDNoE



Quoting the discussion in above thread:

> Filipino is the national language of the Philippines, but it is
> commonly referred to (and registered as) Tagalog, since most of the
> terms therein were derived from it (Tagalog).

This commit targets the 12.0 and adds a new language.
In master (future 14.0 as of today), the Filipino will be dropped.
As fil_PH is only translated on odoo-com project but remains at 0% in
other Transifex project, it is assumed the language switch won't
impact too many people.

closes odoo/odoo#43707

X-original-commit: 0b431e84
Signed-off-by: Martin Trigaux (mat) <mat@odoo.com>