Security: Store datasource passwords encrypted in secureJsonData (#16175)

* Store passwords in secureJsonData

* Revert unnecessary refactors

* Fix for nil jsonSecureData value

* Remove copied encryption code from migration

* Fix wrong field reference

* Remove migration and provisioning changes

* Use password getters in datasource proxy

* Refactor password handling in datasource configs

* Add provisioning warnings

* Update documentation

* Remove migration command, moved to separate PR

* Remove unused code

* Set the upgrade version

* Remove unused code

* Remove double reference

pkg/services/sqlstore/datasource.go

@@ -178,6 +178,10 @@ func UpdateDataSource(cmd *m.UpdateDataSourceCommand) error {
 		sess.UseBool("basic_auth")
 		sess.UseBool("with_credentials")
 		sess.UseBool("read_only")
+		// Make sure password are zeroed out if empty. We do this as we want to migrate passwords from
+		// plain text fields to SecureJsonData.
+		sess.MustCols("password")
+		sess.MustCols("basic_auth_password")
 
 		var updateSession *xorm.Session
 		if cmd.Version != 0 {