Adopt a standard naming convention and signature for debug functions

[jejones3141]

To get the "dd" debugger command to work without having to create an wxplicit mapping from type to function either by hand or by runtime inspection (the latter preventing setting up the command at debugger startup), the debug functions that dd calls should have a type of the form

foo_debug(FILE *fp, foo_t const *)

We add the qualifier becausen

• some support functions with extra parameters are meant to be called by these functions, which pass the additional parameters; the functions we do call can pass fp along, or in the case of src/lib/util/dict_print.c, add fp to the context
• fe_dict_attr_t * has three debug functions
• fr_pair_validate_debug() takes a pointer to an array, and thus can't follow the convention
• virtual_server_{listen, process}_debug() and module_rlm_list_debug() have no parameters