Public link access code is too specific and messy

[PVince81]

The file list should not have to check "if public link, then use this API call or logic" but use the same logic / APIs based on a client instance attached to it.

• For this to work, we first need to unify the APIs in the SDK: Unify public link methods with private files ones owncloud-sdk#375
• Messy: some SDK APIs take the public link token as the first component of the path
• Mix up between "token" and "item" from the URL, in which cases it results to having the token inside the path, which somehow aligns with the SDK API... See draft PR to attempt to fix this here: WIP public link separate token from path #2408

[dschmidt]

Fixed in

• [full-ci] Drive aliases #7430