Hash key for plugin store table and limit plugin ID length (#7915)

* Hash plugin store keys and update column limits

* Limit plugin ID length on install

* Add note to manifest id and allow zero length keys

i18n/en.json

@@ -3558,18 +3558,14 @@
     "id": "app.notification.subject.notification.full",
     "translation": "[{{ .SiteName }}] Notification in {{ .TeamName}} on {{.Month}} {{.Day}}, {{.Year}}"
   },
-  {
-    "id": "app.plugin.prepackaged.app_error",
-    "translation": "Prepackaged plugins cannot be modified."
-  },
-  {
-    "id": "app.plugin.key_value.set.app_error",
-    "translation": "Unable to set key value. See detailed error for more information."
-  },
   {
     "id": "app.plugin.activate.app_error",
     "translation": "Unable to activate extracted plugin. Plugin may already exist and be activated."
   },
+  {
+    "id": "app.plugin.id_length.app_error",
+    "translation": "Plugin Id must be less than {{.Max}} characters."
+  },
   {
     "id": "app.plugin.config.app_error",
     "translation": "Error saving plugin state in config"