Parameterize text input location and search glob

[rstarmer]

The retrieval library and or sample should be parameterized so that it can more readily be used to test against a wider set of target parameters. This issue is related to PR #50 for when that merges.

Acceptance would be the ability to point to a directory as input to a training and validation test.

[sdake]

@MostAwesomeDude @rstarmer @lsdake @sdake I will NOT submit config.py as part of PR #50. Therefore, please consider self-assigning this issue to implement this in the next few days. Until then, we can use hardcode config...

For some inspiration, may I suggest taking a look at the excellent Pytorch Lightning project:

• Environtment Variables
• NVIDIA Amp
• Ground State Inferencing
• Config handling