README rework

[danielmpetrov]

The CoreWiki README was getting bloated with mostly irrelevant to the project information. Newcomers were having difficulties getting started due to lack of relevant documentation and a getting started guide.

Sections removed:

• Those that were strictly about Jeff's stream, since they were practically duplicated from his LiveStream repo. They were replaced with a short sentence and a link to that repository.
• The huge list of 'Topics covered in previous streams'. I found that list to be unhelpful, since there were no links or further references, just a big list of topics.
• Considering for removal: CoreWiki streams index, since Jeff created a youtube playlist. If we decide to keep this index, it should probably reside in another document. The list is currently as a last section to the README.

Sections added:

• Table of contents
• Getting started - live demo, development, deployment, and FAQ
• Features
• Continuous Integration
• Streams Archive (pending removal)

Of course, this PR is just groundwork. More content needs to be added, and suggestions and feedback are appreciated! 👐

Resolves #318 (to some degree)

[csharpfritz]

Thank you for doing this refactoring... it reads a lot better now

[Eldorian]

Just wanted to give a huge thanks for this - this helped a lot. Especially love the section about local development as that was another place I was stuck on for a bit.