Add page to archive user

Users can only be archived by Platform Admin from the user page
(/users/<user_id>). This removes them from all services and orgs and
updates their details.

app/main/views/find_users.py

@@ -1,4 +1,4 @@
-from flask import render_template, request
+from flask import flash, redirect, render_template, request, url_for
 from flask_login import login_required
 
 from app import user_api_client
@@ -37,3 +37,15 @@ def user_information(user_id):
         user=user,
         services=services,
     )
+
+
+@main.route("/users/<uuid:user_id>/archive", methods=['GET', 'POST'])
+@login_required
+@user_is_platform_admin
+def archive_user(user_id):
+    if request.method == 'POST':
+        user_api_client.archive_user(user_id)
+        return redirect(url_for('.user_information', user_id=user_id))
+    else:
+        flash('There\'s no way to reverse this! Are you sure you want to archive this user?', 'delete')
+        return user_information(user_id)