Add synthetic base fixtures and the SONiC E2E job - #2566

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https://zuul.services.osism.tech/t/osism/buildset/4f9c6949cc2d4d018595bd134e451072

✔️ flake8 SUCCESS in 3m 20s
✔️ hadolint SUCCESS in 1m 29s
✔️ mypy SUCCESS in 3m 33s
✔️ python-black SUCCESS in 2m 03s
✔️ container-image-python-osism-build SUCCESS in 4m 54s
✔️ container-image-python-osism-frontend-build SUCCESS in 3m 42s
✔️ python-osism-test-setup SUCCESS in 3m 28s
✔️ python-osism-unit-tests SUCCESS in 4m 27s
✔️ python-osism-integration-tests SUCCESS in 4m 52s
❌ python-osism-sonic-e2e FAILURE in 12m 31s