test(xcatd): cover per-element command-log redaction

Extract the secret set, the command maps and the redaction routines from
xcatd.pm. Drive the real routines, because the module needs daemon
dependencies that the test host does not have.

Cover a multi-word value, a quoted value, spaces around the operator,
the "+=", ",=", "^=", "!=", "=~" and "!~" operators, the community
strings, a secret embedded in a compound argument with and without
quotes, each Getopt::Long password option form with bundles, the "?"
help letter, abbreviations, "+" prefixes and two-dash letters, values
that hold another secret letter, non-secret compact values that a value
option absorbs, long names that start with a secret letter, the mkvm
case forms and compact values, the chvm positional passwords, the mkvm
clone pw= operand, the vCenter cluster passwords, the snmpc site value
through chdef and tabch with compound selectors, the authentication
tokens, and the product keys. Assert that validate() redacts the
argument vector, that the joined result runs through redact_password,
and that the dispatch trace builds its text from redacted arguments.
Keep every attribute and column pair from Schema.pm, so a removed
table-qualified mapping fails the test.