Load LOPs: Support update via context options (replace parm callbacks with expressions)

[BigRoy]

Changelog Description

Replace the Load LOPs parm callbacks with expressions on the file parms to support Solaris Context Options.

Additional info

With this PR, the LOP load nodes now LIVE update based on context options. Meaning, using context-options you can now easily do multi-shot lighting!

Fixes: #111

2024-10-04.10-13-12.mov

Credit: Audio snippet in the background at the beginning is a few seconds of the start from this Youtube video

TODO

• Fix the 'warning message' remaining on the node on path update because it doesn't trigger that callback anymore
• Fix the thumbnails (when enabled) not updating on representation changes.

Testing notes:

1. Load Asset LOP should work consistently
2. Load Shot LOP should work consistently
3. Both should NOT be super slow
4. When using Solaris Context Options the loader should update along live.
   • even with Edit Context Options LOP updates should be live

[MustafaJafar]

This is cool and it's live!

Should we care about these warnings ?

Also, should we have default context options and probably manage them on AYON context change?

[BigRoy]

Should we care about these warnings ?

Yes, we should! I thought I had fixed that already but maybe I forgot to push. Will continue with this.

Will also need to decide what to do with the thumbnails. Before this PR it was created to "auto-update" on context update (but especially now with those being expressions that makes even less sense.) Mark from SideFX says it best:

You should really not be "doing things" as a result of evaluating expressions.

So I guess for now the easiest way is to remove how it's "live" and then just add a "Update thumbnail" button. We can think of better fixes down the line.

[MustafaJafar]

Isn't this cool!
I published three products pointcacherock_1, pointcacherock_2 and pointcacherock_3
and loading them inside a loop works! (as loops are based on context options)

Note: I don't know if my example here is favorite in production. tbh, I don't know what is the best way to publish multiple variants of my pointcache products. maybe it's the correct workflow since different variants of an AYON product are just different AYON products.