create admin util to manage users (create, update/reset pw/api keys, delete), replayd: maybe called replaydctl

[wwlwpd]

Part 1:

• user DB init script
• add user script that uses a library defining members
• web app to use SQLite DB instead of YAML
• API to use SQLite DB instread of YAML

Part 2:

• CLI account create tool that emails credentials to provided email address (used for "invite" mode)
• (lower priority, but important!) admin cli tool that can modify a user (add, disable, remove, change pw, change apikey/secret) #21

Part 3:

• API endpoint that can trigger membership creation give the proper expected input (e.g., confirmation after requesting an account) #22