Automatically initialize PETSc in flcbdfWrappers

* Simplify Comm init so it takes no arguments
* Assume sys.argv is default argv to pass in to PETSc
* Remove PETSc database options
* Automatically initialize DAETK and Comm/PETSc in flcbdfWrappers
* Replace DAETK-Comm with a simple Python comm
* Add some basic tests to verify Comm
* Remove Comm.init() from a few places it is no longer explicitly needed
* Replace Py_PETSC_COMM_WORLD with PROTEUS_COMM_WORLD
Addressed in https://github.com/erdc-cm/proteus/commit/3624429f3c7e05f2e355ba274d7bf6331f793b84