CDL Color Transform Effect

There is a continuum of color management that can potentially be included in OTIO (see #1805). Based on discussions in that thread and #1793 we feel like we know enough to implement a CDL effect schema.

The Schema should be:

```json
{
"OTIO_SCHEMA": "CDLEffect.1",
"metadata": {},
"offset": [
0.0,
0.0,
0.01
],
"power": [
0.5,
0.5,
0.51
],
"slope": [
1.0,
1.0,
1.0
],
"saturation": 0.0,
"process_space": "ACEScct"
}
```
This would be a subclass of the otio `Effect` schema.

By practice - `process_space` should be a name from the [OCIO studio config](https://github.com/AcademySoftwareFoundation/OpenColorIO-Config-ACES/releases).

Review the discussions in #1805 and #1793, then inspect the existing OTIO Effect schema before defining the CDLEffect subclass. Done means the CDLEffect.1 schema supports the listed offset, power, slope, saturation, process_space, and metadata fields, with process_space representing an OCIO studio-config name.

Written by the indexing model from the issue text.