Remove gitlab-ci and migrate fuzz job to GHA (#1996) #108

Job	Run time
set-image	1s
fmt	2m 0s
clippy	9m 2s
spellcheck	1m 12s
clippy-examples (STD)	9m 1s
clippy-examples (WASM)	3m 21s
check (STD)	7m 10s
check (WASM)	1m 36s
dylint	4m 40s
check (RISCV)	1m 38s
build (STD)	12m 21s
build (WASM)	1m 30s
test	14m 17s
examples-test	18m 18s
docs	8m 0s
codecov	20m 59s
examples-contract-build (WASM)	15m 6s
examples-docs	3m 36s
examples-contract-build (RISCV)	2m 35s
measurements / contract-sizes	0s
fuzz	0s
	2h 16m 23s

Provide feedback