liboptimsochost: Switch to GLIP for dbgnoc backend

With the introduction of GLIP, we can factor out most communication
related code into GLIP. This allows us to reuse the communication code
and easier support other communication methods.
RTL: Update ZTEX systems to use GLIP

This updates the system_2x2_cccc_ztex for synthesis and the testbench
variant to use the new GLIP logic backend instead of the old OpTiMSoC-
specific one. This also requires the liboptimsochost changes.