add redis-based index & query endpoint (#112)

Dockerfile

cmd/cli/app/pflags.go

cmd/cli/app/pflags_test.go

cmd/cli/app/search.go

cmd/server/app/root.go

config/rekor.yaml

docker-compose.debug.yml

docker-compose.yml

go.mod

go.sum

openapi.yaml

pkg/api/api.go

pkg/api/entries.go

pkg/api/error.go

pkg/api/index.go

pkg/generated/client/entries/entries_client.go

pkg/generated/client/index/index_client.go

pkg/generated/client/index/search_index_parameters.go

pkg/generated/client/index/search_index_responses.go

pkg/generated/client/rekor_client.go