Translate admin page from old webapp to new webapp

[samuelwshen]

Description

The old webapp's admin page was a place for volunteers to do misc administrative tasks, such as modify categories, edit hours, and view items that were low stock. When translating this page to the new webapp, we do not need to build the ability to modify categories since that is being done separately.

Prior work

To view the admin page, go to testcalnourish.firebaseapp.com, login with an authenticated email, and click the Admin tab. The frontend code for the old admin page is here. I wouldn't lean too much on it though since we do want to refresh the styling for the new webapp.

To see how the old admin page interacted with Firebase, here's the script. We will need to make a new endpoint that updates the hours for the food pantry. Talk to Sam about how this would work.

What we want

We're pretty flexible with this page since it isn't a core page to the webapp. Design-wise, it's pretty open ended. The core thing to get done first is the low stock threshold, then updating hours can come later. We have long term ideas for what we want on this page, so just having an Admin page is a great place to be.