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/components/source/SourceMangaGrid.tsx

@@ -8,6 +8,7 @@
 
 import React from 'react';
 import MangaGrid, { IMangaGridProps } from 'components/MangaGrid';
+import { IMangaCard } from 'typings';
 
 const FILTERED_OUT_MESSAGE = 'There are no Manga matching this filter';