Cleaned up radlog(L_ERR, ... in mod_initialize

to cf_log_err_cs(conf, ...

where appropriate
Added REQUIRED and ATTRIBUTE types for CONF_PARSER

To simplify the rest of the code
Use PW_TYPE_REQUIRED and PW_TYPE_ATTRIBUTE

Checked via "grep", but there are probably more modules
which need converting
Don't call mod_detach() from instantiate

The server core takes care of this
Remove duplicate code