Use typelib instead of XML

For normal compilation, use .typelib files rather than .gir XML files.
This is much faster.

Rather than using libgirepository, which would try to actually load the
libraries, we use a custom parser.

The language server will still read XML because it needs to access
documentation, which is not in the typelib, but that's generally fine
because it's a long lived process and only has to do that once.

blueprintcompiler/language/imports.py

@@ -41,8 +41,14 @@ class GtkDirective(AstNode):
 
         try:
             gir.get_namespace("Gtk", self.tokens["version"])
-        except:
-            raise CompileError("Could not find GTK 4 introspection files. Is gobject-introspection installed?", fatal=True)
+        except CompileError as e:
+            raise CompileError(
+                "Could not find GTK 4 introspection files. Is gobject-introspection installed?",
+                fatal=True,
+                # preserve the hints from the original error, because it contains
+                # useful debugging information
+                hints=e.hints,
+            )
 
 
     @property