Add en_CA locale

[OmeGak]

No description provided.

[ThiefMaster]

I think even if there are no different words (dunno if they have weird (mis)spellings like the Brits do ;)), it should be done via Transifex (cc @tomasr8) for the sake of consistency.

Also, you need to include the locale for momentjs. See this page in the docs or one of the PRs where we added a new language.

[tomasr8]

I added en_CA on transifex, you can pull the (empty) po files with indico i18n pull indico en_CA

[ThiefMaster]

@OmeGak will you add the fixes related to missing locale-specific formatting to this PR or a separate one? Probably it doesn't make that much sense to merge this without the other fixes since the main point of adding en_CA is to get proper l10n

[OmeGak]

This PR should be ready to merge. My last f-push:

• Added all the .po files as pulled from Transifex.
• Added the en-ca locale to indico/web/client/js/jquery/index.js.
• Changed the author of this commit to Indico Team <indico-team@cern.ch>.

Also, @ThiefMaster, the date picker widget respects the en_CA locale once installed properly. I didn't find any other place in Indico where the short format is used.