Skip login screen and try OIDC automatically (if available)

### Current Behavior

Adding OIDC support to DT is easy, given the well documented samples. Also in favour of using SSO wherever possible to get rid of user account drift.

In the current setup this is accomplished through a separate button on the login screens, which becomes available after a few seconds (the backend is consulted). Then the user can click that button and the OIDC flow occurs, leading to the DT dashboard.

But is's not user friendly (one extra click, some weird 'required' message) and behaves different from most SSO setups where the login screen is bypassed

A way to do a local login should remain possible, as fall back for a locally defined admin user - one option could be to use a query param to force the screen to be present

### Proposed Behavior

After checking wether OIDC is available, immediately apply the login with OIDC-flow

### Checklist

- [X] I have read and understand the [contributing guidelines](https://github.com/DependencyTrack/dependency-track/blob/master/CONTRIBUTING.md#filing-issues)
- [X] I have checked the [existing issues](https://github.com/DependencyTrack/frontend/issues) for whether this enhancement was already requested