add global values support (#322)

Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/322
Reviewed-by: luhahn <[email protected]>
Reviewed-by: justusbunsi <[email protected]>
Co-authored-by: cnfatal <[email protected]>
Co-committed-by: cnfatal <[email protected]>

values.yaml

@@ -1,6 +1,14 @@
 # Default values for gitea.
 # This is a YAML-formatted file.
 # Declare variables to be passed into your templates.
+global:
+  imageRegistry: ""
+  ## E.g.
+  ## imagePullSecrets:
+  ##   - myRegistryKeySecretName
+  ##
+  imagePullSecrets: []
+  storageClass: ""
 
 replicaCount: 1