fix: specify modules when autoimport post-processing

[alvarosabu]

This PR fixes the issue with the stable release of post-processing

[alvarosabu]

@Tinoooo @damienmontastier, we have an issue with compatibility because of how we decided to architecture the @tresjs/post-processing package. Nuxt module tries to auto import the default, since there are two modules, I tried adding them but names collide. We need to go another route for the post-processing package and probably have a breaking change there

[damienmontastier]

@alvarosabu Instead of having 2 exports (for three and pmdrs), would it be better to have a UnrealBloom folder, with the Three.js effect and the Pmdrs effect inside?

• UnrealBloom
    - Pmdrs
    - Three
• Glitch
    - Pmdrs
    - Three
• etc..

To call each effect (Glitch, UnrealBloom, etc), we could imagine using either :

• 2 components <GlitchPmdrs /> and <GlitchThree />.

OR

• 1 component <Glitch source=“pdmrs” /> which then dynamically calls the one concerned

[userquin]

@damienmontastier @alvarosabu Tresjs/post-processing#152

[userquin]

I'm going to prepare another PR here (will supersede this PR), we only need to do some hack before registering the imports...