[New] Install and Configure Rocket.Chat as a Chat and Helpdesk Tool (#…

…6519)

* Initial draft of the guide on Rocket.Chat.

* General revisions.

* Tech Edit 1

* Tech Edit 2

* copy edit and added tech steps

* copy edit for feedback

---------

Co-authored-by: Adam Overa <adamovera@protonmail.com>
Co-authored-by: John Dutton <johndutton.update@gmail.com>

ci/vale/dictionary.txt

@@ -736,6 +736,7 @@ Freemarker
 freenom
 fremont
 freshclam
+freshdesk
 friendica
 friendster
 frontend
@@ -1611,6 +1612,7 @@ OKConfig
 okta
 oldstable
 oldfashioned
+omnichannel
 onboarding
 oneof
 ons
@@ -2141,6 +2143,7 @@ smtpd
 smush
 smux
 snakeoil
+snapcraft
 snapd
 snipcart
 snmp
@@ -2701,6 +2704,7 @@ zabbix
 zapier
 zcat
 zend
+zendesk
 zgrep
 zhao
 zigbee