Bug 1072191, 1074613 - Layout normalization follow-ups

- |LayoutLoader._normalizeLayout| is now delegated onto LayoutNormalizer
-- Alternativs chars normalization codes are moved to LayoutNormalizer
- LayoutNormalizer is no longer a singleton (better pattern since it's only used locally)
- textLayoutOverwrites is now normalized
Bug 1084282 - [BB] Change the link for icon fonts
Bug 1016731 - Intermittent page_test.js | page.js > page > appendIcon > "after all" hook | TypeError: GridManager is null r=crdlc
Merge pull request #25209 from mnjul/bug_1074613_normalize_alt_char_and_overwrite_chars

Bug 1072191, 1074613 - Layout normalization follow-ups. r=timdream
Merge pull request #25258 from pacorampas/1084282

Bug 1084282 - [BB] Change the link for icon fonts r=arnau
Merge pull request #25295 from julienw/1016731-fix-page-test

Bug 1016731 - Intermittent page_test.js | page.js > page > appendIcon > ...
test gaia pull
fixing the issue with try-server failing. Rebasing to master
another fix of difference between master and v2.1
another portion of EJ comments
remove whitespaces
newer version of the privacy panel, fixing bugs 1083815, 1083822, 1083857, 1083861, 1083813, 1083794. Bugs left: 1083806, 1083854, 1083800
fixing the ring bug - 1083806