To disable the module you must login to your server's terminal, go to Magento install directory and perform:

php bin/magento module:disable Unirgy_StoreLocator

If full removal is needed, then all extension's files should be removed. Files are located at:

app/code/Unirgy/StoreLocator/

If you want to remove all database traces of the module you should:

DROP TABLE `ustorelocator_location`;

and

DELETE FROM `core_resource` WHERE `code` LIKE 'ustorelocator_setup' LIMIT 1;

You may need to adjust above lines to account for table prefix.

Any traces of the module should be now removed, remember to flush cache and re run compilation if you use it.