Add package registry stack instructions (#937)

- The instructions to `Deploy Gitea Package Registry` from build-support [readme](https://git.vdb.to/deep-stack/stack-orchestrator/src/branch/pm-update-registry-steps/stack_orchestrator/data/stacks/build-support#2-deploy-gitea-package-registry) don't seem to be in a working state
- Updated `package-registry` stack instructions to use deployment pattern

Reviewed-on: cerc-io/stack-orchestrator#937
Reviewed-by: ashwin <ashwin@noreply.git.vdb.to>
Reviewed-by: David Boreham <dboreham@noreply.git.vdb.to>
Co-authored-by: Prathamesh Musale <prathamesh.musale0@gmail.com>
Co-committed-by: Prathamesh Musale <prathamesh.musale0@gmail.com>

stack_orchestrator/data/stacks/package-registry/README.md

@@ -2,4 +2,28 @@
 
 The Package Registry Stack supports a build environment that requires a package registry (initially for NPM packages only).
 
-Setup instructions can be found [here](../build-support/README.md).
+## Setup
+
+* Setup required repos and build containers:
+
+  ```bash
+  laconic-so --stack package-registry setup-repositories
+  laconic-so --stack package-registry build-containers
+  ```
+
+* Create a deployment:
+
+  ```bash
+  laconic-so --stack package-registry deploy init --output package-registry-spec.yml
+  # Update port mapping in the laconic-loaded.spec file to resolve port conflicts on host if any
+
+  laconic-so --stack package-registry deploy create --deployment-dir package-registry-deployment --spec-file package-registry-spec.yml
+  ```
+
+* Start the deployment:
+
+  ```bash
+  laconic-so deployment --dir package-registry-deployment start
+  ```
+
+* The local gitea registry can now be accessed at <http://localhost:3000> (the username and password can be taken from the deployment logs)