added update_Document_LastEdited
- updates the lastedited detail of a document
renaming of insert controller functions for better readability
- packed all insert_XXX functions into the index() function with a
switch/case
- renamed all validate_i_XXX functions to insert_XXX functions
- the function name should tell what the result of it will be and not
 what inside of it are executed (validation, etc pp)
put is_logged_in function into their respective constructor functions