Add configurable admin password via environment variable

- Add ORCHARD_ADMIN_PASSWORD env var to set initial admin password
- When set, admin user created without forced password change
- Add AWS Secrets Manager support for stage/prod deployments
- Add .env file support for local docker development
- Add Helm chart auth config (adminPassword, existingSecret, secretsManager)

Environments configured:
- Local: .env file or defaults to changeme123
- Feature/dev: orchardtest123 (hardcoded in values-dev.yaml)
- Stage: AWS Secrets Manager (orchard-stage-creds)
- Prod: AWS Secrets Manager (orch-prod-creds)

.env.example

@@ -0,0 +1,7 @@
+# Orchard Local Development Environment
+# Copy this file to .env and customize as needed
+# Note: .env is gitignored and will not be committed
+
+# Admin account password (required for local development)
+# This sets the initial admin password when the database is first created
+ORCHARD_ADMIN_PASSWORD=changeme123