Add/Update documentation for SSO

[SetZero]

Body of the issue

I tried to set-up SSO on my InvenTree instance and ran into a couple of issues while getting it to work. The current documentation for InvenTree's SSO seems to be outdated and/or confusing:

• It mentions a "Add Social Applications" page which don't seem to exist anymore or is at a completly different location now. The example image social_account_add.png doesn't have the mentioned "Add Social Application" in it either.
• From what it looks like the config.yaml is currently the only option to add a SSO provider. But maybe that's related to [FR] Make OIDC configurable via API/while running #4715 as this is still open?

If you could confirm these points I'd also be willing to help updating the documentation.

[SchrodingersGat]

@SetZero thanks for raising this. The documentation clearly needs work.

The image you linked is wrong - it should be pointing to the django admin section:

Currently SSO applications must be created via the django admin panel - they are not available via the API.

If you would like to assist in improving the documentation around this, it would be greatly appreciated!

[nharmer1309]

@SchrodingersGat

After the update I am not able to navigate to the /admin as it redirects, was not able to locate social accounts settings page, can you help please?

[matmair]

@nharmer1309 depending on your setup you might need another slash, so /admin/

[SchrodingersGat]

@SetZero are you still willing to help us out with some documentation improvements here?

[SetZero]

@SchrodingersGat I will probably only get to do it next weekend, if that's not an issue

[SchrodingersGat]

That's great, thanks!