feat: Delete all unlinked entries at once (TagStudioDev#617)

This technically removes the usefulness progress indicator, but brief
testing on my end had it delete ~8000 entries in less time than it took
me to see if the progress indicator was properly indeterminate or not

Author: Toby222

tagstudio/src/core/utils/missing_files.py

@@ -60,10 +60,7 @@ def fix_missing_files(self) -> Iterator[int]:
                 self.missing_files.remove(entry)
             yield i
 
-    def execute_deletion(self) -> Iterator[int]:
-        for i, missing in enumerate(self.missing_files, start=1):
-            # TODO - optimize this by removing multiple entries at once
-            self.library.remove_entries([missing.id])
-            yield i
+    def execute_deletion(self) -> None:
+        self.library.remove_entries(list(map(lambda missing: missing.id, self.missing_files)))
 
         self.missing_files = []

tagstudio/src/qt/modals/delete_unlinked.py

@@ -81,24 +81,15 @@ def refresh_list(self):
 
     def delete_entries(self):
         pw = ProgressWidget(
-            window_title="Deleting Entries",
+            window_title=f"Deleting {self.tracker.missing_files_count} Entries",
             label_text="",
             cancel_button_text=None,
             minimum=0,
-            maximum=self.tracker.missing_files_count,
+            maximum=0,
         )
         pw.show()
 
-        iterator = FunctionIterator(self.tracker.execute_deletion)
-        files_count = self.tracker.missing_files_count
-        iterator.value.connect(
-            lambda idx: (
-                pw.update_progress(idx),
-                pw.update_label(f"Deleting {idx}/{files_count} Unlinked Entries"),
-            )
-        )
-
-        r = CustomRunnable(iterator.run)
+        r = CustomRunnable(self.tracker.execute_deletion)
         QThreadPool.globalInstance().start(r)
         r.done.connect(
             lambda: (