Fuzzing: Add CIFuzz

[AdamKorcz]

Description: What this PR does
Adds CIFuzz to jsonparsers OSS-fuzz integration. In short, CIFuzz is a service offered by OSS-fuzz to run jsonparsers fuzzers during the CI to prevent bugs from being introduced.
In this PR the fuzz time is set to 600 seconds but can be changed.

More about CIFuzz can be found here: https://google.github.io/oss-fuzz/getting-started/continuous-integration/

Benchmark before change:

Benchmark after change:

For running benchmarks use:

go test -test.benchmem -bench JsonParser ./benchmark/ -benchtime 5s -v
# OR
make bench (runs inside docker)