added view for managing users in a list #135

[bryanmontz]

Issues covered

https://github.com/verse-pbc/issues/issues/135

Description

Adds the view for managing which users are in a list.

How to test

Existing List:

1. Navigate to Your Lists
   A. From the side menu
   B. From the feed picker dropdown, then Manage Your Lists.
2. Tap on any list.
3. Tap the ellipsis button at the top right.
4. Tap Manage Users.
   Here you'll be presented with a search view with an empty search bar. The contents of the view below will be the existing users in the list. Typing in the search bar will bring up search results. The circular icon over the avatar indicates whether or not that user is currently in the list. Users can be added and removed here, and tapping Done will save the list.

Creating a new list:

1. Navigate to Your Lists (see above)
2. Tap the New button at the top right.
3. Type in a name and optional description, and tap the Next button at the top right.
4. Tap the Save button.
   The list is created and added to Your Lists.

Screenshots/Video

Post screenshots or video showing your changes, ideally showing how the app worked before and after these changes. Delete this section if this PR contains no visual changes.

Before	After
replaceme	replaceme