Add text-lb.wikimedia.org and switch CNAMEs to it

Commit 2b7a05f1 replaced the DYNC target of $project-lb.wikimedia.org
hosts to just the text-lb georesource. Go one step further and introduce
a new text-lb.wikimedia.org hostname and switch all CNAMEs across the
board to point there.

This is essentially a slightly modified
s/(foundation|mediawiki|wikibooks|wikimedia|wikinews|wikipedia|wikiquote|wikisource|wikiversity|wiktionary|wikidata|wikivoyage)-lb/text-lb/

The actual $project-lb CNAMEs (DYNCs) stay for now, as we'll need to
wait for at least one TTL to make sure they are not referenced and used
anymore.

Change-Id: I28434e0f0a22e1e25632352cf22efb25532c0b54