Define KeeShare file reference per-computer

[ckieschnick]

Currently the KeeShare data is stored as annotation to the shared groups. This does not allow to move the database to another location or environment.

Summary

Until now, the scenario to use the same database with KeeShare enabled under multiple environments (i.e. using the database in a multiboot environment, ..) was not really considered for the KeeShare feature. The current representation of path does not consider, that the same database may be used to share from different environments.

Desired Behavior

The sharing feature should work independent for each client without the need to change the database itself.

Possible Solution

We suggest to change the reference path to a constant which should be resolved using the settings of the current KeePassXC instance rather than the database. This way, each client needs a list of shared locations which may be associated with the open database. This allows to export to the same location after setting up the proper paths for each client (we may even introduce some flags in the share container to ensure that an export does use the matching export container).

[ckieschnick]

According to the discussion in #2799, we'll implement the feature using some kind of os identifier to select the correct path for now.

[bin101]

@ckieschnick Do you have this still on your radar? And btw, does the "relative path" PR consider that unix systems uses / as seperator and windows ? I am not that familiar with cpp.