Convert files in themes/ services/ contexts/ to TS

Convert all Javascript files in `client/src/themes`, `client/src/service`, `client/src/contexts` to Typescript.
Convert SvgIcon, Input, ConversationView, Button components to Typescript

Gitlab #30

Change-Id: I0d0505c28e21c771906edf8d5e7b8ce36126fa64
diff --git a/client/src/themes/default.js b/client/src/themes/Default.ts
similarity index 100%
rename from client/src/themes/default.js
rename to client/src/themes/Default.ts
diff --git a/client/src/themes/ThemeDemonstrator.js b/client/src/themes/ThemeDemonstrator.tsx
similarity index 95%
rename from client/src/themes/ThemeDemonstrator.js
rename to client/src/themes/ThemeDemonstrator.tsx
index d989569..977deed 100644
--- a/client/src/themes/ThemeDemonstrator.js
+++ b/client/src/themes/ThemeDemonstrator.tsx
@@ -9,9 +9,9 @@
   TakePictureButton,
   TipButton,
   UploadPictureButton,
-} from '../components/buttons';
-import { NickNameInput, PasswordInput, RegularInput, UsernameInput } from '../components/inputs';
-import defaultTheme from './default';
+} from '../components/Button';
+import { NickNameInput, PasswordInput, RegularInput, UsernameInput } from '../components/Input';
+import defaultTheme from './Default';
 
 export const ThemeDemonstrator = () => {
   return (