enh(barracuda): add message mode, enh storage and mails modes

[cgagnaire]

Adds a new message mode that check the number of queued messages.

perl centreon_plugins.pl --plugin=network::barracuda::bma::snmp::plugin --mode=message --hostname=10.1.2.3 --subsetleef=1
OK: Number of messages in queue: 6, Last message archived 3s ago | 'message.queued.count'=6;;;0; 'message.archived.last.second'=3s;;;0;

Enhance the storage mode to add effective and on disk size of message per hour, day and total (delta per seconds).

perl centreon_plugins.pl --plugin=network::barracuda::bma::snmp::plugin --mode=storage --hostname=10.1.2.3 --subsetleef=1
OK: Storage space firmware used: 71.00%, mail and logs used: 89.00% - Effective size hourly: 820.00 B, daily: 18.27 KB, delta: 0.00 B/s - On disk size hourly: 483.00 B, daily: 11.30 KB, delta: 0.00 B/s | 'storage.firmware.space.usage.percentage'=71.00%;;;0;100 'storage.maillog.space.usage.percentage'=89.00%;;;0;100 'storage.effective.hourly.bytes'=820B;;;0; 'storage.effective.daily.bytes'=18706B;;;0; 'storage.effective.delta.bytespersecond'=0B/s;;;0; 'storage.ondisk.hourly.bytes'=483B;;;0; 'storage.ondisk.daily.bytes'=11573B;;;0; 'storage.ondisk.delta.bytespersecond'=0B/s;;;0;

Change mails mode to output delta per seconds volume of emails instead of delta (named total).

perl centreon_plugins.pl --plugin=network::barracuda::bma::snmp::plugin --mode=mails --hostname=10.1.2.3 --subsetleef=1
OK: Number of inbound mails hourly: 9049, daily: 77853, delta: 2.20/s - Number of outbound mails hourly: 0, daily: 36, delta: 0.00/s - Number of internal mails hourly: 0, daily: 0, delta: 0.00/s | 'mails.inbound.hourly.count'=9049;;;0; 'mails.inbound.daily.count'=77853;;;0; 'mails.inbound.delta.persecond'=2.20/s;;;0; 'mails.outbound.hourly.count'=0;;;0; 'mails.outbound.daily.count'=36;;;0; 'mails.outbound.delta.persecond'=0.00/s;;;0; 'mails.internal.hourly.count'=0;;;0; 'mails.internal.daily.count'=0;;;0; 'mails.internal.delta.persecond'=0.00/s;;;0;