Implement Fuzz testing

[sudiptob2]

The CNCF Fuzzing Initiative in collaboration with OSS-Fuzz provides a fuzzing infrastructure that enables CNCF projects to leverage coverage-guided continuous fuzzing. Envoy Proxy already benefits from extensive fuzz testing, so applying the same approach to Envoy Gateway will ensure similar robustness and reliability.

Tasks

Develop initial set of fuzz tests

• Create a design document for fuzz testing #5426
• Implement fuzzers for Gateway API resource to IR translation #5428
• Implement fuzzer for Gateway API to XDS #5462
• Add seed corpus directory

Integrate Continuous Fuzzing with OSS-Fuzz

• Add script to build the fuzzers in oss-fuzz infra. #5492
• Add envoy gateway in the OSS-Fuzz repository #5501
• Add a brief documentation on running fuzz tests locally using oss-fuzz infra. #5502

References

1. Fuzzing library Go-fuzz
2. Fuzzing Infrastructure: OSS-Fuzz
3. Best Practices: OSS-Fuzz ideal integration