chore: general clean up and improve usefulness of readme.md

[eshaben]

As a part of Roadmap Issue 321, this PR fixes a few small issues found when auditing the ganache docs:

• [x] consistent punctuation
• [x] consistent capitalization
• [x] consistent use of inline code formatting
• [x] add navigation to top of readme (similar to ganache-core)
• [x] add navigation within sections where applicable

[eshaben]

Closing this PR... the work is not necessary