processed review comments

Closes L2SDP-422

See merge request desp/hdl!143

Resolve L2SDP-473

Closes L2SDP-473

See merge request desp/hdl!141

Resolve L2SDP-411

Closes L2SDP-411

See merge request desp/hdl!142

Resolve L2SDP-464

Closes L2SDP-464

See merge request desp/hdl!140

updated yaml file for unb2c_minimal and unb2c_boad

Closes L2SDP-463

See merge request desp/hdl!139

Resolve L2SDP-418

Closes L2SDP-418

See merge request desp/hdl!138

st_histogram updates. Ready for integration in LOFAR2.

Closes L2SDP-364

See merge request desp/hdl!137

files for lofar2_unb2b/c_sdp_station

-All test benches pass OK.

-All TB still pass OK (tb_tb_st_histogram).

-Added 5 TBs that use an unlocked, drifting sine wave as input.
-All test benches pass OK.

-Changed TB parameters.

Resolve L2SDP-431

Closes L2SDP-431

See merge request desp/hdl!136

simultaneous read/write issue;
-Added signed/unsigned histogram readout to TB;
-All test benches pass OK.