babeld: justify "running-config" meaning in CLI

babeld: justify "running-config" meaning in CLI

The primary focus of this commit is to make "show running-config"
command display more current configuration, including some of the bits
previously seen in the output of "show babel running-config". Besides
that, the following commands were renamed for consistency with the
syntax of other components:

"debug *" to "debug babel *" (and moved to top level)
"show babel running-config" to "show babel parameters"

* babel_interface.c
  * show_babel_running_config(): rename to show_babel_parameters(),
    update syntax pattern, don't call show_babeld_configuration()
  * babel_if_init(): update respectively
  * babel_enable_if_config_write(): new VTY helper for static
    babel_enable_if
* babel_interface.h: add extern declaration
* babel_main.c: unset all debug options by default
  * show_babel_main_configuration(): remove debug options decoder
* babel_zebra.c
  * babel_debug(): rename to debug_babel(), update syntax pattern
  * no_babel_debug(): rename to no_debug_babel(), update syntax pattern
  * babelz_zebra_init(): update respectively
  * debug_babel_config_write() new VTY helper for static debug_type
* babel_zebra.h: add extern declaration
* babeld.c
  * babel_config_write(): add the code to output "debug babel *",
    "router babel", "redistribute *" and "network *" statements
  * show_babeld_configuration(): dismiss
* babeld.h: remove extern declaration
* babeld.texi: update for renamed commands
* babeld.conf.sample: idem, add debug statements block