Text field should use changes instead of changeCallbacks in order to make followField work with them

[DegrangeM]

Currently, text field use changeCallbacks.

Other fields, like select, instead use changes.

The followField method only work on fields using changes, it doesn't work with field using changeCallbacks.

For more consistency and to allow followField to work with text field, text field should also use changes.

changeCallbacks should be marked as deprecated but changeCallbacks should also be supported for a while for compatibility untill all library are updated (not sure if there is a lots of library using it).

More information here : https://h5p.org/node/1141889