Fixed localization issues of the login page.

Since form strings were not created for each request, some strings were
displayed in mixed languages.

Customizations made to the profiles app have been removed as well.

Fixes bug 2260.
Create 'pootle/assets' before building the static data.
Make MIN_SIMILARITY for fuzzy matching configurable.
Fixed for duplicated strings with placeables.
Changed singular strings to allow proper translation.

Some languages need to use singular form without the quantifier. Remove
it to allow proper translations for those languages.