[core] Remove unwanted localization and colType exports

[flaviendelangle]

Part of #2227

Breaking changes

• Stop using constants for colDef types, we have a type GridNativeColTypes so we can directly use the string.

-const isColString = col.type === GRID_STRING_COLUMN_TYPE;
+const isColString = col.type === 'string';

-const isColNumber = col.type === GRID_NUMBER_COLUMN_TYPE;
+const isColNumber = col.type === 'number';

-const isColDate = col.type === GRID_DATE_COLUMN_TYPE;
+const isColDate = col.type === 'date';

-const isColDateTime = col.type === GRID_DATETIME_COLUMN_TYPE;
+const isColDateTime = col.type === 'dateTime';

-const isColBoolean = col.type === GRID_BOOLEAN_COLUMN_TYPE;
+const isColBoolean = col.type === 'boolean';

• Stop exporting the localization object before the merge with the core values.

- plPLGrid
- ruRUGrid
- skSKGrid
- ukUAGrid
- zhCNGrid