refactor: add Pubkey, Privkey, NoteId string aliases

This is a non-behavioral change in preparation for the actual switchover
from Strings to Ids. The purpose of this kit is to reduce the size of
the switchover commit which is going to be very large.

damus/Views/Profile/ProfileView.swift

@@ -31,7 +31,7 @@ func follow_btn_txt(_ fs: FollowState, follows_you: Bool) -> String {
     }
 }
 
-func followedByString(_ friend_intersection: [String], profiles: Profiles, locale: Locale = Locale.current) -> String {
+func followedByString(_ friend_intersection: [Pubkey], profiles: Profiles, locale: Locale = Locale.current) -> String {
     let bundle = bundleForLocale(locale: locale)
     let names: [String] = friend_intersection.prefix(3).map {
         let profile = profiles.lookup(id: $0)
@@ -90,7 +90,7 @@ struct ProfileView: View {
         self._followers = StateObject(wrappedValue: followers)
     }
 
-    init(damus_state: DamusState, pubkey: String) {
+    init(damus_state: DamusState, pubkey: Pubkey) {
         self.damus_state = damus_state
         self._profile = StateObject(wrappedValue: ProfileModel(pubkey: pubkey, damus: damus_state))
         self._followers = StateObject(wrappedValue: FollowersModel(damus_state: damus_state, target: pubkey))
@@ -493,7 +493,7 @@ struct ProfileView_Previews: PreviewProvider {
 }
 
 struct KeyView: View {
-    let pubkey: String
+    let pubkey: Pubkey
 
     @Environment(\.colorScheme) var colorScheme
 
@@ -566,7 +566,7 @@ extension View {
     }
 }
 
-func check_nip05_validity(pubkey: String, profiles: Profiles) {
+func check_nip05_validity(pubkey: Pubkey, profiles: Profiles) {
     guard let profile = profiles.lookup(id: pubkey),
           let nip05 = profile.nip05,
           profiles.is_validated(pubkey) == nil