Starting updates to docs

[ericspod]

Description

This updates the docs with a minor fix to the bundle metadata example and adds diagrams to help explain MONAI, and bundles vs. MAPs.

Types of changes

• Non-breaking change (fix or new feature that would not break existing functionality).
• Breaking change (fix or new feature that would cause existing functionality to change).
• New tests added to cover the changes.
• Integration tests passed locally by running ./runtests.sh -f -u --net --coverage.
• Quick tests passed locally by running ./runtests.sh --quick --unittests --disttests.
• In-line docstrings updated.
• Documentation updated, tested make html command in the docs/ folder.

[vikashg]

I hope this is useful.
Thanks

[wyli]

Thanks, it looks good to me.

[wyli]

/build

thank you, follow-up documentation updates could be included in further PRs.