Consider switching from base58 to base32 to improve URL compatability

[cinnamon-bun]

Problem

Workspace names need to be case sensitive to preserve their base58 secrets.

URL locations are supposed to be NOT case sensitive, and some URL parsers will lowercase them for you.

This matters if we want to make our own URL scheme like earthstar:// without fighting the URL parser.

Solution?

Switch workspace and author addresses to lowercase base32 encoding.

Secrets will be 52 chars long instead of 44. This isn't significantly worse.

See this comment for details.

[cinnamon-bun]

Done!

[christianbundy]

Congrats on the change!