docs: build-from-source path, and normalise LICENSE for detection

The referenced GHCR image is private until somebody flips it in the GitHub UI,
and there is no REST route for container package visibility, so the documented
install path did not actually work for anyone outside the org. Building from
source has no dependencies to fetch and takes seconds, so it belongs in the
README rather than being assumed.

LICENSE had leading whitespace that stopped GitHub detecting it as Apache-2.0.

Author: stubbi

LICENSE

@@ -1,5 +1,4 @@
-
-                                 Apache License
+Apache License
                            Version 2.0, January 2004
                         http://www.apache.org/licenses/
 

README.md

@@ -65,6 +65,16 @@ kubectl -n <gateway-namespace> get ciliumenvoyconfig
 kubectl apply -f deploy/
 ```
 
+`deploy/deployment.yaml` references `ghcr.io/paperclipinc/pqc-admission-webhook`.
+If that image is not pullable for you, build your own, which takes a few seconds
+and has no dependencies to fetch:
+
+```sh
+docker build -t <your-registry>/pqc-admission-webhook:v1 .
+docker push  <your-registry>/pqc-admission-webhook:v1
+# then set that image in deploy/deployment.yaml
+```
+
 ### Configuration
 
 | Variable | Default | Meaning |