OE0-84: Automatizing Pulling modules from source and using local instances.

[malinowskikam]

This PR requires #72 to be available to use, but does not depend on it.

Changes:

• Implemented install_module_locally admin command, allowing to fetch and install modules from remote repositories on local setup

Usage:

• install_module_locally invoice - fetches module openimis-be-invoice from repository (url from openimis.json, using develop branch) next to openimis-be_py directory and istalls it as editable library (pip)
• install_module_locally invoice --url <url> --branch <branch> --path <path> - optional arguments allowing to override default settings, also allowing to add a module not present in openimis.json (results in new openimis.json entry)
• install_module_locally all - fetches and installs all modules present in openimis.json (allows --path and --branch to be customized)

https://openimis.atlassian.net/browse/OE0-84