Lucas/t 231 timebox i can create a company at the same time im creating (#140)

This PR is a bit messy:

adding graphql schema
adding create company creation on company select on People page
some frontend refactoring to be continued

---------

Co-authored-by: Charles Bochet <charles@twenty.com>

front/src/components/people/EditablePeopleFullName.tsx

@@ -0,0 +1,39 @@
+import { useState } from 'react';
+import PersonChip from '../chips/PersonChip';
+import { EditableDoubleText } from '../editable-cell/EditableDoubleText';
+
+type OwnProps = {
+  firstname: string;
+  lastname: string;
+  onChange: (firstname: string, lastname: string) => void;
+};
+
+export function EditablePeopleFullName({
+  firstname,
+  lastname,
+  onChange,
+}: OwnProps) {
+  const [firstnameValue, setFirstnameValue] = useState(firstname);
+  const [lastnameValue, setLastnameValue] = useState(lastname);
+
+  function handleDoubleTextChange(
+    firstValue: string,
+    secondValue: string,
+  ): void {
+    setFirstnameValue(firstValue);
+    setLastnameValue(secondValue);
+
+    onChange(firstnameValue, lastnameValue);
+  }
+
+  return (
+    <EditableDoubleText
+      firstValue={firstnameValue}
+      secondValue={lastnameValue}
+      firstValuePlaceholder="First name"
+      secondValuePlaceholder="Last name"
+      onChange={handleDoubleTextChange}
+      nonEditModeContent={<PersonChip name={firstname + ' ' + lastname} />}
+    />
+  );
+}