Doing only 5 LDPC iterations by default leads to a poor reception
performance, and correspondingly many retransmissions. Increase to 8 as
the new default to improve user experience.

system_core is the core reserved for DPDK control threads. It was
hardcoded to 0, but it seems that one some systems, CPU 0 cannot be
reasonably isolated from kernel threads. Make it therefore configurable
(default: 0)

Closes: #732 (suggestion 1)
Suggested-by: Andrew Sergeev <andrew.sergeev@adtran.com>

- PUSCH target increase: lower PUSCH target requires !2373
- sdr_addrs is USRP-specific, not needed for O-RAN

- Add the O-RAN 7.2 FHI library, interfacing with OSC xRAN library (E
  release)
- Add Findxran.cmake to detect the library and headers, including
  version information
- Test for numa and DPDK presence
- Add patch for OSC xRAN to make interworking possible
- Add sample config files for LiteOn, Benetel, and VVDN units.

Documentation is provided in the next commit.

Co-authored-by: Raymond Knopp <raymond.knopp@eurecom.fr>
Co-authored-by: Cedric Roux <cedric.roux@eurecom.fr>
Co-authored-by: Manish Kumar Singh <manish1.kumar@amd.com>
Co-authored-by: thamizhselvan.k <thamizhselvan.k@vvdntech.in>
Co-authored-by: rajeshwari.p <rajeshwari.p@vvdntech.in>
Co-authored-by: Hongzhi Wang <hongzhi.wang@openairinterface.org>
Co-authored-by: Sofia Pison <Sofia.Pison@eurecom.fr>

This reverts commit daf8b950

This reverts commit bf0c6941

This reverts commit 96554bef

Delete min_rxtxtime_pdsch from config file gnb.sa.band78.fr1.106PRB.2x2.usrpn300.conf to get 0 errors in iperf with COTS