ci: Build fixes

- Simplify builds by separating dev/stable workflows
- Fix Helm deploy key
- Remove deploy_key.env (already using deploy key in secrets)
- Fix paths matching on push and pull_request triggers
- Fix possible issues with tag difference between ERPNext and Frappe (add tag resolving step before pushing)
- Don't login, push Docker images and release Helm chart on forks
- Don't test on version 12 (there's no test for this version)
- Remove frappe-installer (from chore: use github actions #525)
- Fix badges in readme

.github/scripts/install-deps-and-test.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+set -e
+
+sudo apt-get install -y w3m
+
+./tests/check-format.sh
+./tests/docker-test.sh
+
+# This is done to not to rebuild images in the next step
+git clean -fdx