Consider allowing some customizations to locale names, such as lower-casing

[denyshon]

In some places where we insert a locale name in a string (e.g., in https://github.com/mozilla/kitsune/blob/80e64bd34bf9ffd921b60816131119e77a3294d8/kitsune/kbforums/views.py#L432), that name is sorta hard-coded and therefore imposes limitations on string l10n. For example, since it's always capitalized, languages where locale names should not be capitalized must put it at the beginning of the string.

We should consider providing some customization options (e.g., two variables: one lower-cased and one capitalized) in such cases. Maybe there are other customizations needed for different languages?

[denyshon]

Given that we only expose the l10n version of the page to the target locale, maybe it would make sense to drop {l} altogether, specifying "English" and asking localizers to replace it with their own locale language in a comment. To be honest, that sounds like a nearly perfect option to me