Move the interactive map into a new MapLibreShim framework

Second step towards loading MapLibre on demand: everything that touches it now
lives in one framework, so that framework can later be left unlinked.

The interactive map view, its annotation view and the coordinate animator move
into MapLibreShim, which reaches the app through MapLibreShimProtocol. The app
side keeps its MapLibreMapView call site and becomes a thin wrapper that builds
a MapViewConfiguration, passing the app-only pieces (map style URLs, marker
views, tint colour) across as closures so the shim needs nothing from the app.

LocationAnnotation loses its MapLibre conformance and becomes a plain struct,
with the shim mapping it onto its own annotation type. MapLibre's log
forwarding moves into the shim as well, since TargetConfiguration can no longer
reach it.

ElementX/MapLibre/MapLibreInterface/Sources/MapModels.swift

@@ -6,6 +6,7 @@
 // Please see LICENSE files in the repository root for full details.
 //
 
+import CoreLocation
 import Foundation
 
 /**
@@ -33,3 +34,23 @@ public enum MapLibreError: Error, Hashable {
     case failedLoadingMap
     case failedLocatingUser
 }
+
+/// The severity of a map log message forwarded to the app.
+public enum MapLogSeverity {
+    case error
+    case warning
+    case info
+    case debug
+    case verbose
+}
+
+/// A marker shown on the map, identified so that it can be moved in place when its coordinate changes.
+public struct MapAnnotation {
+    public let id: String
+    public let coordinate: CLLocationCoordinate2D
+    
+    public init(id: String, coordinate: CLLocationCoordinate2D) {
+        self.id = id
+        self.coordinate = coordinate
+    }
+}