Simplify MaRC licensing

[ossama-othman]

Is your feature request related to a problem? Please describe.
MaRC components currently ship under three licenses:

• MaRC library: LGPL 2.1+
• MaRC program: GPL 2.0+
• MaRC documentation: FDL 1.3

This is overly complicated, and potentially confusing.

Describe the solution you'd like
MaRC licensing should be simplified, ideally using a single license like BSD-3-Clause or MIT.