Add Bionic on supported deb packages list (#90)

* Add Bionic on supported deb packages list

* Remove support for Trusty from management server documentation.

* minor update

Co-authored-by: Andrija Panic <45762285+andrijapanicsb@users.noreply.github.com>

Author: GabrielBrascher

source/installguide/management-server/_pkg_repo.rst

@@ -65,8 +65,8 @@ DEB package repository
 ~~~~~~~~~~~~~~~~~~~~~~
 
 You can add a DEB package repository to your apt sources with the
-following commands. Please note that only packages for Ubuntu 14.04 LTS
-(Trusty) and Ubuntu 16.04 (Xenial) are being built at this time. DISCLAIMER: Ubuntu 12.04 (Precise) is no longer supported.
+following commands. Please note that only packages for Ubuntu 16.04 (Xenial) 
+and Ubuntu 18.04 (Bionic) are being built at this time. Ubuntu 14.04 (Trusty) is no longer supported.
 
 Use your preferred editor and open (or create)
 ``/etc/apt/sources.list.d/cloudstack.list``. Add the community provided