ci: simplified build-and-release pipeline + Dockerfile

.dockerignore

@@ -1,18 +1,18 @@
-/*
-!/VERSION.txt
-!/build_envoy
-!/ci
-!/distribution/docker
-!/configs/google-vrp
-!/configs/*yaml
-!/linux/amd64/release.tar.zst
-!/linux/amd64/schema_validator_tool
-!/linux/amd64/router_check_tool
-!/linux/amd64/config_load_check_tool
-!/linux/arm64/release.tar.zst
-!/linux/arm64/schema_validator_tool
-!/linux/arm64/router_check_tool
-!/linux/arm64/config_load_check_tool
-!/local
-!/test/config/integration/certs
-!/windows
+# /*
+# !/VERSION.txt
+# !/build_envoy
+# !/ci
+# !/distribution/docker
+# !/configs/google-vrp
+# !/configs/*yaml
+# !/linux/amd64/release.tar.zst
+# !/linux/amd64/schema_validator_tool
+# !/linux/amd64/router_check_tool
+# !/linux/amd64/config_load_check_tool
+# !/linux/arm64/release.tar.zst
+# !/linux/arm64/schema_validator_tool
+# !/linux/arm64/router_check_tool
+# !/linux/arm64/config_load_check_tool
+# !/local
+# !/test/config/integration/certs
+# !/windows