cmake: Copyright/attibution cleanup

Most of these files had inaccurate copy-paste headers, as the files are
now vastly different than those mentioned. These will all just fall under
the "meta-data" category in upcoming licenses.

Per discussion with FindLibBladeRF.cmake author, the text in
FindLibTecla.cmake was unnecessary, and has been removed.
libbladeRF, utils: Moving ezusb code out of lib into utils

With future license-related cleanup, all GPLv2 programs will live
in the utilities directory. As such, ezusb.c has been moved out
of the library, and the bladeRF-cli utility has been modified to
use this directly.