CDClient cleanup and optimization (#1023)

* CDClient cleanup and optimization

- Use static function to get table name
- Remove unused GetName function
- Replace above function with a static GetTableName function
- Remove verbose comments
- Remove verbose initializers
- Remove need to specify table name when getting a table by name
- Remove unused typedef for mac and linux

* Re-add unused table

Convert tables to singletons

- Convert all CDClient tables to singletons
- Move Singleton.h to dCommon
- Reduce header clutter in CDClientManager

dDatabase/Tables/CDRailActivatorComponent.cpp

@@ -43,12 +43,6 @@ CDRailActivatorComponentTable::CDRailActivatorComponentTable() {
 	tableData.finalize();
 }
 
-CDRailActivatorComponentTable::~CDRailActivatorComponentTable() = default;
-
-std::string CDRailActivatorComponentTable::GetName() const {
-	return "RailActivatorComponent";
-}
-
 CDRailActivatorComponent CDRailActivatorComponentTable::GetEntryByID(int32_t id) const {
 	for (const auto& entry : m_Entries) {
 		if (entry.id == id)