Make JSQMessagesViewController strings translatable

[2-4601]

(I'm fusing #784 and #1033 into one issue.)

Three strings are not available for translation at Transifex because they rely on the strings of JSQMessagesViewController.

The strings are:

• "Load Earlier Messages"
• "Send"
• "New Message"

Currently affected languages (based on what's available at the upstream project):

• az_AZ
• bg_BG
• bs
• ca
• cs
• da
• el_GR
• es
• fil
• fi
• hr
• hu
• lv
• nb_NO
• sl
• sv_SE

Work around:
Submit a translation as a pull request to JSQMessagesViewController (see jessesquires/JSQMessagesViewController#237) and wait for it to get included in Signal iOS.

[michaelkirk]

This will be edit: (partially) solved with #1255.

(It took me at least 2 minutes to remember how to switch back to english.)

Thanks for the upstream update @2-4601 👍