Suggestion for README: adjust order of items, include some links to documentation & add small pre-reqs section

[isc-eneil]

Links to consider adding:

1. 'Modify the Environment File' from 'Deploy A Container Stack' docs, in container.env section
2. 'Create the Base Configuration JSON File' from 'Deploy A Container Stack' docs, in hs-base-config.json section

Ordering suggestion:

• Place docker-compose command + explanation at the bottom of the page, past the sections on each file

Ideas for pre-requisites section:

• HS image loaded (necessary since you need a HS image to understand/fill out the instance-specific environment variables in container.env)
• docker login completed (if this is actually always necessary-- I'm not sure)