Added static var $moduleId in each module service instead of const var in MarketingToolboxModuleService.

Method loadData moved to MarketingToolboxModuleService.
Revert "Added static var $moduleId in each module service instead of const var in MarketingToolboxModuleService."

This reverts commit 7859104b29f97f4378d2661420191d5d9d90b010.
Added const MODULE_ID in each module service instead of const vars in MarketingToolboxModuleService.

Method loadData moved to MarketingToolboxModuleService.