Update format of curriculum directory

[lichtefeld]

This collection of requests for changing how we process the curriculum was developed from my experience with the process on M4 core. I had to do some manual realignment of the files to get a format that looks like the following. That was a reasonable process for the first full curriculum (and 'ok' for 30 scenes) but will not be able to be a manual process as the size of our curriculum grows to hundreds of situations. Most of the requests here are for @blakeharrison-ai and @shengcheng as they arise during the curriculum generation & perception processing stage.

For curriculum generation we may potentially have many files for each situation (scene) presented to the learner. Some of these files could become temporally ordered (e.g. start and end). As such I'd like to ask that we organize each situation in our curriculum in its own directory. Therefor we'd get a directory layout like the following inside a root directory like phase3_m4_core which is the name of the curriculum:

- situation_0
- situation_1
- situation_2

Inside a specific situation folder would be the resulting curriculum from @blakeharrison-ai's simulation tool. Ideally I'd want to use a numerical indicator in the file name for temporal order (e.g. 0 -> 1 -> 2), in the list below this number is replaced by X. Right now I believe the current outputs are:

• depth_X.png
• pcd_rgb_X.ply
• pcd_semantic_X.ply
• rgb_X.png
• semantic_X.png

Therefor situation_0 in a curriculum with only a single image would look like the following:

- depth_0.png
- pcd_rgb_0.ply
- pcd_semantic_0.ply
- rgb_0.png
- semantic_0.png

If situation_0 is an action then _0, _1, _2 versions of the files above would indicate the temporal order. Additional files may exist as we decide on the full set of available outputs. (A video file of the entire situation seems very reasonable)

When the curriculum in this format is delivered to @shengcheng so he can run visual processing this process ideally would a) add a feature.yaml file into the existing situation directory. That way the curriculum maintains all relevant pieces that have been created/processed in its lifetime. That will make coordinating the file display easier in the UI tool.