Feature: collection sharing (design planning)

[pbiering]

This relates to

• Calendar sharing support? #1499
• Feature: Secret, auth-less, read-only URLs #1977
• Collection sharing (WIP) #885 - stale and potentially too complex

Planning now to implement this by using SQlite database (perhaps also central text based config files), softlinking is not supported on Windows (and not supporting implicit permission adjustments).

• by-map
• by-token
• controlled by WebUI (in case of SQlite also via SQL/CLI)

by-map:

• Table with association per line: target-user | owner | collection | permissions | enabled

by-token

• Table with association per line: token | owner | collection | permission | enabled

WebUI control by extension of protocol (feeding that it is a share and the defined permissions)

• owner can insert/update/delete association per collection
• by-map: target-user will see the collection with its permission

Comments?

At least for the WebUI I need support.