Rename buttons to open media and files

Make the wording consistent with other buttons in the list (only use
nouns, no verbs).

Shorten the wording and hopefully make it more clear to users the
difference between the two.

Monal/Classes/ContactDetails.swift

@@ -389,13 +389,13 @@ struct ContactDetails: View {
                 let sharedUrl = HelperTools.getSharedDocumentsURL(forPathComponents:[accountJid, displayName])
                 if UIApplication.shared.canOpenURL(sharedUrl) && FileManager.default.fileExists(atPath:sharedUrl.path) {
                     NavigationLink(destination: LazyClosureView{MediaGalleryView(contact: contact.contactJid as String, accountID: contact.accountID)}) {
-                        Text("View Media Gallery")
+                        Text("Shared Media")
                     }
 
                     Button(action: {
                             UIApplication.shared.open(sharedUrl, options:[:])
                     }) {
-                        Text("Show shared Media and Files")
+                        Text("Shared Files")
                     }
                 }
 

Monal/Classes/MediaGallery.swift

@@ -27,7 +27,7 @@ struct MediaGalleryView: View {
             }
             .padding()
         }
-        .navigationTitle("Media Gallery")
+        .navigationTitle("Shared Media")
         .onAppear {
             fetchDownloadedMediaItems()
         }