MINOR: config: add command-line -dC to dump the configuration file

MINOR: config: add command-line -dC to dump the configuration file

This commit adds a new command line option -dC to dump the configuration
file. An optional key may be appended to -dC in order to produce an
anonymized dump using this key. The anonymizing process uses the same
algorithm as the CLI so that the same key will produce the same hashes
for the same identifiers. This way an admin may share an anonymized
extract of a configuration to match against live dumps. Note that key 0
will not anonymize the output. However, in any case, the configuration
is dumped after tokenizing, thus comments are lost.