feat: add CSP and other security related headers in the oCIS proxy service (#8777)

* feat: add CSP and other security related headers in the oCIS proxy service

* fix: consolidate security related headers - drop middleware.Secure

* fix: use github.com/DeepDiver1975/secure

* fix: acceptance tests

* feat: support env var replacements in csp.yaml

vendor/github.com/unrolled/secure/Makefile

@@ -0,0 +1,14 @@
+.PHONY: help test ci
+.DEFAULT_GOAL := help
+
+help: ## Displays this help message.
+	@awk 'BEGIN {FS = ":.*?## "} /^[a-zA-Z_-]+:.*?## / {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}' $(MAKEFILE_LIST)
+
+test: ## Runs the tests, vetting, and golangci linter.
+	golangci-lint run ./...
+	go test -v -cover -race -count=1 ./...
+	go vet .
+
+ci: ## Runs on the tests and vetting checks (specific for CI).
+	go test -cover -race -count=1 ./...
+	go vet ./...