Change `SignedInTabView` to show actual views instead of just `Text`

[Majekdor]

Currently, SignedInTabView looks like this:

struct SignedInTabView: View {
    var body: some View {
        TabView {
            Text("Home")
                .tabItem {
                    Label("Home", systemImage: "house")
                }

            Text("Search")
                .tabItem {
                    Label("Search", systemImage: "magnifyingglass")
                }

            Text("Clubs")
                .tabItem {
                    Label("Clubs", systemImage: "person.3")
                }

            Text("")
                .tabItem {
                    Label("Profile", systemImage: "person.circle")
                }
        }
    }
}

We should be showing our actual views instead of just Text.