* backend: support exposing info about a particular invite, fixes part of #35
new apis are:
- GET /users/invite/{token}?email={email} - no auth needed, get invite to new user
- GET /users/me/invite/{token} - with auth, to get invite to join an archive for an existing user
* get archive.name as well if invite is adding to an archive
* first camelCase typo
- adapt nginx config to work both in docker and k8s, using env vars to set urls
backend: additional fixes:
- use env vars with nginx config
- fix settings api route
- when sending e-mail, use the Host header for verification urls when available
- prepare Dockerfile with full build from scratch in image, (disabled 'yarn install' for faster builds for now)
- fix accept invite api for existing user to /archives/accept-invite/{token}
* backend:
- refactor invite system, move to separate InviteOps object, used by archives and user
- supporting three invite use cases:
1) superuser invites any user not registered, not added to any archive
2) archive admin invites any user not registered, add to one of their archives
3) archive admin invites existing registered user, add to one of their archives
- support superadmin invite via /users/invite (fixes#37)
- superadmin invite has no archive set and does not add user to archive
- don't send verification email when accepting from invite, fixes#50
- use different email template / accept url for existing user invite, eg, `/invite/accept/`
- fix default token value in chart
