clean up MDWF QUDA interface

[walkloud]

Prepare chroma:devel to add support for more MDWF solvers in QUDA.

• Change pipeline=1 -> pipeline=0 as default param value, which is needed for CG solvers (ref. K. Clark)
• add ability to set verbosity = QUDA_DEBUG_VERBOSE in nef solvers by adding a Debug param to the xml struct