Adding FileUpload control and updated related components

src/myfasthtml/core/bindings.py

@@ -129,6 +129,14 @@ class DataConverter:
     pass
 
 
+class LambdaConverter(DataConverter):
+  def __init__(self, func):
+    self.func = func
+  
+  def convert(self, data):
+    return self.func(data)
+
+
 class BooleanConverter(DataConverter):
   def convert(self, data):
     if data is None: