Add files

.ci_scripts/install_packages.sh

.github/workflows/unit-tests.yaml

.gitignore

CMakeLists.txt

include/coap.h

include/dhcp.h

include/dns.h

include/dns_map.h

include/hashmap.h

include/header.h

include/http.h

include/igmp.h

include/packet_utils.h

include/sha256.h

include/ssdp.h

src/CMakeLists.txt

src/coap.c

src/dhcp.c

src/dns.c

src/dns_map.c