[ticket/14272] Use html5 valid input elements
* marc1706/ticket/14272:
[ticket/14272] Allow input of floats for filesize
[ticket/14272] Use input type number instead of text in avatars
[ticket/14272] Assign min and max values for avatar driver settings
[ticket/14272] Define min and max values for avatar width and height
[ticket/14272] Disable not toggled form elements
[ticket/14272] Make sure phpbb_avatar_manager was defined
[ticket/14272] Remove useless check
[ticket/14272] Fix invalid or missing min/max settings
[ticket/14272] Assign min/max for all allowed types
[ticket/14272] Only use maxlength and size for allowed input elements