Doc updates

[codeananda]

After reading this morning and being confused by certain things, I wanted to pull more info into the docs to note some issues.

I haven't used reStructuredText before so not sure if my links are formatted correctly but I hope they are!

[codeananda]

Amazing thanks!

I was thinking of also updating the front page/GitHub README to cross out the sections

• Disk serialization
• Custom storage implementation (to implement spatial indexing in ZODB, for example)

Or put a * next to them or something

[mwtoews]

Most of these docs are ~13 years old, so some updates would be welcome!