Update and improve serial protocol #2084

Job	Run time
Check c99 compilation	19s
Check codebase format with clang-format	3s
Test examples without router	24s
Build raweth transport on ubuntu-latest	18s
Run unit tests on ubuntu-latest	33s
Check compilation with unstable API	22s
Build Zenoh from source	5m 50s
Test attachments	43s
Test examples memory leak	1m 21s
Test multicast and unicast fragmentation	48s
Modular build on ubuntu-latest (1, 1, 1, 1)	51s
Build and test in single thread on ubuntu-latest	46s
Modular build on ubuntu-latest (1, 1, 1, 0)	43s
Modular build on ubuntu-latest (1, 1, 0, 1)	1m 49s
Modular build on ubuntu-latest (1, 1, 0, 0)	46s
Modular build on ubuntu-latest (1, 0, 1, 1)	49s
Modular build on ubuntu-latest (1, 0, 1, 0)	46s
Modular build on ubuntu-latest (1, 0, 0, 1)	46s
Modular build on ubuntu-latest (1, 0, 0, 0)	39s
Modular build on ubuntu-latest (0, 1, 1, 1)	46s
Modular build on ubuntu-latest (0, 1, 1, 0)	31s
Modular build on ubuntu-latest (0, 1, 0, 1)	36s
Modular build on ubuntu-latest (0, 1, 0, 0)	28s
Modular build on ubuntu-latest (0, 0, 1, 1)	31s
Modular build on ubuntu-latest (0, 0, 1, 0)	30s
Modular build on ubuntu-latest (0, 0, 0, 1)	34s
Modular build on ubuntu-latest (0, 0, 0, 0)	31s
	23m 3s

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