Create an intermediate repos folder to better organize openedx-translations & update scripts and config files

[Carlos-Muniz]

Reasoning:
In the future, there will probably be 100+ repositories keeping their translation files in openedx-translation. All of these directories will be in the root directory making it annoying to access configuration, workflows, etc. An intermediate directory containing the repository related directories will keep things better organized.

Contingencies:
This step can be done before the main steps, and will probably be easier to do earlier as there will be less changes to make in the workflow and transifex.yml files.