Separate user and auth providers, add config for rest user

[ishank011]

This PR

• separates the config for the auth and user provider services. Previously, these used to have the same driver, which restricted using different configs for both.
• adds the config for the rest user driver
• adds the gatewaysvc parameter to EOS fs.
• adds uid_claim and gid_claim parameters to OIDC auth.

[micbar]

@refs @PVince81 do we need to document that?

[micbar]

@ishank011 What is the user story behind this change?

[ishank011]

@micbar at CERN we use OIDC for authentication, and then we have a REST API service which provides details about the other users and group resolution functionality. Previously, both the authprovider (basic auth) and userprovider services used the same driver, which didn't work for us because if we tried to set the value of this driver to rest, it would fail because there's no basic auth driver with that name. So the first two changes are about enabling that. Since the rest driver is CERN-specific, maybe we shouldn't add it here, but in a separate fork.

This change adds the capability to eos fs to call the userprovider service to lookup UIDs for users and vice versa. So the third bullet adds the config for that that.

The fourth change allows us to look up additional claims, namely uid and gid, from the OIDC tokens.

[labkode]

@micbar this change is not only useful for us but to many deployments of current ownCloud. Let me explain that.
Users may authenticate to an IDP using for example OIDC that is backed by an LDAP/AD directory service. However, when searching for users and getting extra attributes for the user, the IdP lacks this capabilities, so you need to go to LDAP/AD. This PR allows for that.

[labkode]

@butonic @ishank011 needs rebase.

[ishank011]

@butonic can you restart the build? An unrelated test failed.

=== RUN   TestRegisterGRPCEndpoint
--
37 | --- FAIL: TestRegisterGRPCEndpoint (0.20s)
38 | external_test.go:54: Deregister on cancelation failed. Result-length should be zero, got 1
39 | FAIL

[butonic]

move this to the bottom of the struct properties, so we have string first, then int ...
some checks down the line might be picky about this ... 🤷‍♂️

[butonic]

and do a quick rebase,pls. then I'll merge

[ownclouders]

Here is an overview of what got changed by this pull request:

Clones removed
==============
+ pkg/command/users.go  -1
+ pkg/command/authbasic.go  -1
         

See the complete overview on Codacy