Improve bloom docs

[Tinoooo]

Is your feature request related to a problem? Please describe.
The bloom effect seems like it is not working when used with the default parameters.

Describe the solution you'd like
The docs should convey how to use the bloom effect so it is visible in the scene.

[alvarosabu]

@Tinoooo agree, more than improve the docs, why don't we improve the DX and add some defaults so it's at least visible?

[Tinoooo]

@Tinoooo agree, more than improve the docs, why don't we improve the DX and add some defaults so it's at least visible?

I'm not sure about this. One the one hand it adds DX on the other we stray away from the effect defaults.

[Tinoooo]

will be fixed in #123