OAuth2: Implement OAuth 2.0 Implicit Grant

[pietrygamat]

I have checked the following:

• [X] I've searched existing issues and found nothing related to my issue.

Describe the feature you want to add

Bruno being primarily a testing tool should support OAuth2 Implicit Flow despite it being obsolete - because the fact that new apps should not use it does not mean legacy apps we are working with aren't.

The feature has been requested previously here https://github.com/usebruno/bruno/issues/1003#issuecomment-1863309018, https://github.com/usebruno/bruno/issues/119#issuecomment-1805679198 and https://github.com/usebruno/bruno/issues/1901 .

Mockups or Images of the feature

implicit.webm

[caviyacht]

When is this going to be merged in? Bruno seems like it could be very useful to us, but we 100% need the implicit grants...