Separate script for locomotion, add import from po file

* Create script to import from Locamotion, with possibility to choose between local or remote repo.
* Add script to import single .po file (fix issue #102)
* Move functions to get CLI or GET parameter to Utils class with tests.
* Move readme to [wiki](https://github.com/pascalchevrel/langchecker/wiki)
Not strictly for this PR, but in my list_localizers repo I moved the CLI initialization to its own file so as to not have to repeat that for all the commands, maybe we could do something similar given we are having more command scripts now:
https://github.com/pascalchevrel/list_localizers/blob/master/app/inc/cli_init.php
ex of use from a script:
https://github.com/pascalchevrel/list_localizers/blob/master/app/commands/getLocalizer.php#L2