Add remember subcommand

[cmccomb]

Add a memory mechanism for yo.

• Things can be added to memory through: yo remember [things to remembers]
• Memory can be loaded into context with yo --memory [query].
• Things can be forgotten with yo forget [description].

[cmccomb]

Initial implementation can dump everything to be remembered into a dot file (maybe the settings dot file in #13).

A more nuanced implementation would use RAG.