docs: update installation with new OS support
docs: update installation with new OS support

At the time of writing, a couple things are broken:
1. The SLES 12, Jessie, and Xenial Cloudera repo files contain unsubstituted
   template variables.
2. The SLES 12 Cloudera kudu package has a dependency (cyrus-sasl-lib) that
   does not exist on SLES 12.

I'm testing a patch to fix #2 and we're trying to fix #1 live. I did verify
that the SLES 12 packages work if installation is forced.

Change-Id: I2f51b55561f18fbe28d6bf4ed507dfba65947dc0
Reviewed-on: http://gerrit.cloudera.org:8080/4128
Tested-by: Kudu Jenkins
Reviewed-by: Alexey Serbin <864f6b82bd94e8dda64141d4274519ee66e0102e@cloudera.com>
Reviewed-by: Todd Lipcon <2c763d726a8c2f6afda9be7e0e56a2caa6bb5e6b@apache.org>

helifu/kudu,helifu/kudu,InspurUSA/kudu,EvilMcJerkface/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,cloudera/kudu,helifu/kudu,andrwng/kudu,andrwng/kudu,cloudera/kudu,andrwng/kudu,EvilMcJerkface/kudu,cloudera/kudu,cloudera/kudu,andrwng/kudu,helifu/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,InspurUSA/kudu,helifu/kudu,InspurUSA/kudu,EvilMcJerkface/kudu,andrwng/kudu,cloudera/kudu,EvilMcJerkface/kudu,andrwng/kudu,cloudera/kudu,cloudera/kudu,cloudera/kudu,EvilMcJerkface/kudu,helifu/kudu,InspurUSA/kudu,andrwng/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,helifu/kudu,helifu/kudu,InspurUSA/kudu,EvilMcJerkface/kudu,andrwng/kudu,cloudera/kudu,helifu/kudu,InspurUSA/kudu,andrwng/kudu