Add Facebook's Hydra style config management

[nily-dti]

Instead of enforcing the user to have multiple similar configuration files we will store all attributes to reconstruct the experiment configuration file for any specific trial so that it in this way can be shared with others.

• Determine how Hydra is autocompleting the keys (in the OmegaConf obj).

ECFs can be created in multiple ways, either:

• Directly from the command line (at run)
• Manually (before run)
• Automatically through AST (iif code is Python)

If there exists no ECFs and the user has not specified the (key, value) pairs in the command line, abort mission!

Default values are not allowed, but how do we enforce this?

[omry]

Happy to chat about how Hydra can fit with Tracker.

Btw, did we happen to chat at CoRL over your poster?