Move all localization files into locale structure

[krisgesling]

Is your feature request related to a problem? Please describe.
Currently language files are split across locale and vocab.

Describe the solution you'd like
These can be merged under locale and consideration for a better file structure within that directory should be given.

Context
locale is a newer addition that can store all language files. The older convention is to split these across dialog, regex and vocab directories. Each locale/lang-code/ directory can contain any type of sub-directory structure and Mycroft will traverse these. However each language directory should be kept consistent.