Refine use of `input_dir` as both an absolute or relative path

[underchemist]

It's currently possible to pass an absolute path to the upload function which will impact the s3 keys that are uploaded. Ideally the behaviour is normalized between relative and absolute path and better documented.

Possible options:

• Instead of uploading the entire path, only use the containing parent directory as part of the s3 key e.g.
  • "C:\Users\username\data\collection" -> "s3://upload-bucket/collection/..."
• Strip drive prefix if a windows path

Context from customer

 This is great. I skimmed the SDK reference and the example. My initial 2c, I would talk about the input_dir being a relative path in the documentation as someone (aka me) will forget.

 I typically default to passing in a Path object when I am handling files instead of strings. It might even be worth building in a check whether the input_path is absolute or relative. Or perhaps you take a input directory and a project_name (str). All your call. Just my 2c.

We identified some possible rework on the both the lidar and lcd datasets this week which we are working through. It may be a couple of weeks before I am ready to upload. I'll keep you posted when I try it out