Update Kibana installation instructions for Debian and RPM

See https://github.com/elastic/stack-docs/pull/198
The Getting started guide contains Kibana installation instructions here:
https://www.elastic.co/guide/en/elastic-stack-get-started/master/get-started-elastic-stack.html#install-kibana

The "deb or rpm" instructions use tar.gz files. They ought to be updated to match the specific instructions in https://www.elastic.co/guide/en/kibana/master/deb.html#install-deb and https://www.elastic.co/guide/en/kibana/master/rpm.html#install-rpm

Ideally the instructions can be re-used so they stay in synch

Start with the Getting started guide's install-kibana section and compare its deb or rpm instructions with the linked Kibana deb.html and rpm.html pages. Update the guide so both package instructions match the referenced pages and can be reused to stay synchronized.

Written by the indexing model from the issue text.