HPCC-12327 Configgen should extract and write LDAPServer config

This pull request adds a new "-ldapservers" parameter. When specified, configgen
will parse the specified environment.xml file and write to STDOUT a block
containing all the settings for each LDAP Server configured.

Signed-off-by: William Whitehead <william.whitehead@lexisnexis.com>
Merge pull request #6490 from RussWhitehead/configgen_504

HPCC-12327 Configgen should extract and write LDAPServer config

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>