Default sweeper class to read hyperparameters

**Is your feature request related to a problem? Please describe.**
A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
Need a class that will read hyperparameters from a sweep config file

**Describe the solution you'd like**
A clear and concise description of what you want to happen.
A class that will:
- read hyperparameters from file
- instantiate a sweep object that will be able to pass those hyperparams to a tango run

**Describe alternatives you've considered**
A clear and concise description of any alternative solutions or features you've considered.
Not applicable

**Additional context**
Add any other context or screenshots about the feature request here.
This issue is a part of a larger project: Hyperparameter sweeps #143