Fix custom AYON OTIO export range mismatches.

[robin-ynput]

Changelog Description

resolve #31
When working with the new publisher, we found out some mismatch between OTIO native exporter ranges and custom AYON ones. This PR fixes this.

Additional info

In details the mismatches were:

• potential embedded timecode not detected for movie and image sequence
• Gap clip source range not starting from 0 but record range in parent
• timeline fps override not detected
• marker source range not remapped to clip available range
• media source ranges not rescaled when timeline fps != source media fps

This PR focuses on making the ranges consistent between both exporters. It does not report all potential mismatch when exporting metadata, effects, names, ...

Testing notes:

1. Export a timeline using custom AYON OTIO exporter

from ayon_resolve.api import lib
from ayon_resolve.otio import davinci_export as otio_export

otio_timeline = otio_export.create_otio_timeline(
  lib.get_current_resolve_project(),
  timeline=lib.get_current_timeline()
)
otio_export.write_to_file(otio_timeline, filepath)

2. Export the same timeline using native OTIO exporter (Resolve >= 18.5)

from ayon_resolve.api import bmdvr, lib

timeline = lib.get_current_timeline()
timeline.Export("C:\\path\\to\\export_native.otio", bmdvr.EXPORT_OTIO)

3. Compare the resulting files and ensure clips' source_range and available_range match

4. My own test cases and results can be found here:

• qt_and_qt_embedded_tc.zip
• img_seq_timeline_25fps_source_24fps.zip
• img_seq_timeline_24fps_source_24fps.zip
• export_gap_and_markers.zip