Docs: Add instructions on how to make a Mine.

[julie-sullivan]

Suggestion from Penchy:

1. Two places could be candidates for the "Create Your Mine" documentation:

1. https://intermine.readthedocs.io/en/latest/system-requirements/software/git/

On this webpage, the "Local Installation" could be thought as the advanced installation options for skilled InterMine developers. "Create Your Mine" could be thought as the preliminary installation for beginners.

2. https://intermine.readthedocs.io/en/latest/get-started/tutorial/

On this webpage, the "Create Your Mine" could be used for the create BioTest Mine initially, and then downloaded the "malaria-data.tar.gz" data for the following steps.

2. The "Create Your Mine" content is just introducing the make_mine command and the setup.sh shell, which could give the impatient beginners a quick view of the InterMine.

[julie-sullivan]

per @pengchy