Switched to O3 with no inlining optim level for debug builds
Debug builds are mostly used for gcov while it seems a bad idea(-O3), with O0 the
FSW uses more than 100% CPU in normal mode so the treadoff is to switch to O3 without
inlining, this preserves the 1 to 1 relation between code and gcov counters.
Removed unused function and implemented scrubbing perriod counter
- removed send_dumb_hk function since it is useless
- added a new CMake build option 'FSW_Instrument_Scrubbing' to count scrubbing
cycles and deduce scrubbing period. When enabled, this will steal the
lfr_fpga_version[BYTE_0] field from houskeeping packets.