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/components/Message.js b/client/src/components/Message.js
index e36b0da..114b401 100644
--- a/client/src/components/Message.js
+++ b/client/src/components/Message.js
@@ -6,9 +6,9 @@
 import React, { useCallback, useMemo, useState } from 'react';
 import { useTranslation } from 'react-i18next';
 
-import { EmojiButton, MoreButton, ReplyMessageButton } from './buttons';
+import { EmojiButton, MoreButton, ReplyMessageButton } from './Button.tsx';
 import ConversationAvatar from './ConversationAvatar';
-import { OppositeArrowsIcon, TrashBinIcon, TwoSheetsIcon } from './svgIcons';
+import { OppositeArrowsIcon, TrashBinIcon, TwoSheetsIcon } from './SvgIcon.tsx';
 
 dayjs.extend(isToday);
 dayjs.extend(isYesterday);