Sort imports from all files

Add "prettier" script in `package.json` to check if all files are
compliant.

Sort all imports and format all files by running `npm run lint -- --fix`
followed by `npm run prettier -- --write`.

Gitlab #29

Change-Id: Id80402d1344c3bc611f66a46cffeee5f2c375bd8
diff --git a/client/src/components/NewContactForm.js b/client/src/components/NewContactForm.js
index db0ce31..9862453 100644
--- a/client/src/components/NewContactForm.js
+++ b/client/src/components/NewContactForm.js
@@ -1,6 +1,6 @@
-import { useState } from 'react';
-import { InputBase, InputAdornment } from '@mui/material';
 import { SearchRounded } from '@mui/icons-material';
+import { InputAdornment, InputBase } from '@mui/material';
+import { useState } from 'react';
 
 export default function NewContactForm(props) {
   const [value, setValue] = useState('');