Allow for mulit-user setup

[ninsbl]

Currently WebGRASS is compiled for, and run as one specific user.
In multi-user environments with multi-user GRASS DBs, that causes (or at least can cause) severe problems for data security/integrity (users might work in mapsets in parallel for example). Also there would be no way to distinguish access rights for mapsets for different users if all are treated as the same. Finally, when a console will be added in future, all users will be able to see and modify all other user`s data...
Thus a multi-user setup (where logins are mapped to system users) will be quite essential for usage esp. in enterprise settings.
I understand, this is likely also a more longterm development related to #19...

[epifanio]

As early stage of development we are trying to first finalize a working prototype where is possible to:

• execute basic GRASS commands
• rendering of both raster and vector layers
• basic map interaction (query values for both raster and vector)

the prototype will work in a single user setup.

Of course the plan for webgrass is to run in a multiuser.

There are different possibilities to handle multiuser, like:

• have webgrass running with PAM-LDAP so to run a single-user instance of webgrass for each unix user available on the server.
• webgrass sandboxed in a docker container, ideal for security reasons. and spawn a container for each user logging-in with O-auth

This is the direction, but unfortunately will take a while before we can handle multiuser access, for now the focus is on the single user app. btw, @ninsbl thanks a lot for testing and for valuable feedback!

[ninsbl]

Thank for clarification! Looking forward to a working prototype which can be used for showcasing the potential of your "early stage of development work".
Single user can be a good start! I can see some possible applications for also a single user setup; e.g. sampling of time series by less GRASS experienced users in my institute...
It would be nice if inaccessible mapsets could be filtered from the list of mapsets for such cases...