Added uinames to ambiguously named nodes

[JGamache-autodesk]

I am trying to build UI names for a MaterialX node picker and had to create a hardcoded list of names to expand. Seeing this as not particularly good I wondered if uiname metadata could not be added at the source to add proper display names in cases where they could not be algorithmically generated.

This involves a few editorial decisions. I do not have any strong feelings about these and am open to iterate.

• UI names are title case. Seemed the best practice. Can be lowercased algorithmically if DCC prefers lower or sentence case as long as acronyms are preserved.
• Names that concatenate words together were split. Using the description in section comments if it sounded better.
• Names that were already split with "_" were left untouched. They can be title cased via code. 100% coverage might be better.
• Names that contained an acronym were processed to capitalize the acronym correctly. Especially useful for glTF and OpenPBR related nodes.
• Names that truncated some of the words were expanded (ifgreatereq, premult, etc).
• Well known truncated mathematical functions were not expanded (sin, cos, atan2, exp... probably the worst editorial decision of the bunch, but I plead "best practice" since this is how math is written in textbooks).

TODO: Fix this line in usdMtlx parser to try to find uiname metadata for the Label Sdr metadata.

[kwokcb]

@ld-kerley I like this idea of UI separation / reuse. Throwing out a possible syntax ui that can reference interface elements: nodedefs and compound nodegraphs:

  <!-- Associate with a nodedef interface -->
  <ui name="UI_def_name" uiname="My UI Name" nodedef="ND_def_name" >
    <input name="in1" uigroup="group1" uiname="Input 1" doc="This is the first input" />
    <input name="in2" uigroup="group2" uiname="Input 2" doc="This is the second input" />
    <output name="out1" uigroup="group2" uiname="Output 2" doc="This is the first output" />  
  </ui>

  <!-- Associate with a compound graph interface -->
  <ui name="UI_graph_name" uiname="My UI Graph Name" nodegraph="my graph" >
    <input name="in1" uigroup="group1" uiname="Input 1" doc="This is the first graph input" />
    <input name="in2" uigroup="group2" uiname="Input 2" doc="This is the second graph input" />
    <output name="out1" uigroup="group2" uiname="Output 2" doc="This is the first graph output" />  
  </ui>

Can take this thread outside this PR but thought I'd drop this in as if you want a consistent naming you might also want to consider consistency for input / output names as well.

[ld-kerley]

Just to revitalize this thread a little - at least the repetitive edits in the stdlib file look like they could benefit from the recently proposed template idea to consolidate the edits to fewer places....

[jstone-lucasfilm]

I really like the idea of this new documentation, @JGamache-autodesk, but I agree with the consensus that we should wait until we have a nodedef system that doesn't require duplication of text across type variants.

For now, I'd recommend that we close out this PR (as great of an idea as it is), and keep this in the back of our minds until we're ready to move forward with a nodedef templating or documentation sharing system.