Add dj-rest-auth

[matmair]

This PR:

• Adds various endpoints to use the currently available auth/registering functions via the API
• Adds JWT as an auth method (simpler to use in SPA - related to Epic: React #3901)

TODO:

• test registering endpoint
• add social connect endpoints
• security review?
• extend docs

Fixes #3978

[SchrodingersGat]

Does this work with existing SSO solutions?

[matmair]

@SchrodingersGat that is still TODO

[matmair]

@SchrodingersGat do we want to continue supporting all social connection options with #3901 or should we cut down the options for the first version?

[SchrodingersGat]

By "cut down" do you mean still supporting key ones (e.g. google / microsoft)?

[matmair]

@SchrodingersGat it took a bit but it seems like we can maintain support for almost all providers (all that support OAuth2).

Exceptions are (updated 2310 CEST):

Found handler that is not yet ready for platform UI: `draugiem`
Found handler that is not yet ready for platform UI: `evernote`
Found handler that is not yet ready for platform UI: `500px`
Found handler that is not yet ready for platform UI: `flickr`
Found handler that is not yet ready for platform UI: `openstreetmap`
Found handler that is not yet ready for platform UI: `persona`
Found handler that is not yet ready for platform UI: `pocket`
Found handler that is not yet ready for platform UI: `steam`
Found handler that is not yet ready for platform UI: `telegram`
Found handler that is not yet ready for platform UI: `trello`
Found handler that is not yet ready for platform UI: `tumblr`
Found handler that is not yet ready for platform UI: `xing

I will work on adding support for Keycloak, OpenId and Twitter. Are you ok with waiting for FRs for the rest?

[matmair]

Ok, I have to revise that; there is a Twitter OAuth2 and OIDC endpoint; I added keycloak so it should be good to go.
The only thing missing is an endpoint to get all available providers and a few small refactors.

[SchrodingersGat]

I will work on adding support for Keycloak, OpenId and Twitter. Are you ok with waiting for FRs for the rest?

Absolutely - I don't think it makes sense to spend a bunch of effort for integrations that may never actually be used.

[SchrodingersGat]

Does this replace our existing SSO login views completely?

[matmair]

No, it just exposes them in another way. Under the hood the same functional code is used.

[matmair]

Closes #3978

[SchrodingersGat]

@matmair ready for merge? Does this need any additional docs?

[matmair]

@SchrodingersGat I got it to a point where the settings do not need to change so no new docs needed.

[SchrodingersGat]

Well, great! Thanks :)