remove manually created typing d ts file (#249)

* Rename file

".d.ts" files are files that are automatically generated during compilation (in case option is set) and shouldn't be created manually.

* Export types and interfaces

* Add missing imports

src/screens/Extensions.tsx

@@ -21,6 +21,7 @@ import AppbarSearch from 'components/util/AppbarSearch';
 import { useQueryParam, StringParam } from 'use-query-params';
 import { Virtuoso } from 'react-virtuoso';
 import { Typography, useMediaQuery, useTheme } from '@mui/material';
+import { IExtension } from 'typings';
 
 const LANGUAGE = 0;
 const EXTENSIONS = 1;