Get PETSc default settings from parameter files

[baagaard-usgs]

Description

We currently store default PETSc settings in parameter files in share/settings as well as programatically set the parameters in C++.

Desired Solution

Use the parameter files in share/settings as the storage of the parameters and read them in via Python based on the user parameters.

Gotcha: We do not want to override user specified parameters.

[baagaard-usgs]

This should be relatively easy to do in Pyre 1 by programmatically loading the solver settings from a YAML file. Settings loaded programmatically have lowest priority (will be overwritten by user settings).