Remove sensu images

They have been deprecated in Ussuri [1].

[1]: https://review.opendev.org/#/c/711636/

Upstream dropped it:

IMPORTANT: Sensu Core reached end-of-life (EOL) on December 31, 2019, and we permanently removed the Sensu EOL repository on February 1, 2021.

Change-Id: I0cfde46c29eedce77c70c1c677220814a801ff3a
(cherry picked from commit 0cfd362)

Author: hrw

doc/source/matrix_aarch64.csv

@@ -74,7 +74,6 @@ rsyslog,C,C,C,C,N,C
 sahara,C,C,C,C,N,C
 searchlight,N,C,N,C,N,C
 senlin,C,C,C,C,N,C
-sensu (deprecated),C,C,N,N,N,N
 skydive,N,N,N,N,N,N
 solum,N,C,N,C,N,C
 storm,C,C,C,C,N,C

doc/source/matrix_x86.csv

@@ -75,7 +75,6 @@ rsyslog,C,C,C,C,C,C
 sahara,C,C,C,C,C,C
 searchlight,N,C,N,C,N,C
 senlin,C,C,C,C,C,C
-sensu (deprecated),C,C,C,C,N,N
 skydive,C,C,C,C,C,C
 solum,N,C,N,C,N,C
 storm,C,C,C,C,C,C

docker/base/sources.list.ubuntu

@@ -33,9 +33,6 @@ deb http://ubuntu-cloud.archive.canonical.com/ubuntu bionic-updates/ussuri main
 # Qdrouterd repo
 #deb http://ppa.launchpad.net/qpid/released/ubuntu/ bionic main
 
-# Sensu repo
-#deb https://sensu.global.ssl.fastly.net/apt bionic main
-
 # Opendaylight repo
 #deb http://ppa.launchpad.net/odl-team/carbon/ubuntu xenial main
 

docker/sensu/sensu-api/Dockerfile.j2

@@ -1094,7 +1094,7 @@
         'uid': 42466,
         'gid': 42466,
     },
-    'sensu-user': {
+    'sensu-user': {  # unused used (sensu dropped)
         'uid': 42467,
         'gid': 42467,
     },

docker/sensu/sensu-base/Dockerfile.j2

@@ -138,7 +138,6 @@
         "nova-spicehtml5proxy",  # Missing spicehtml5 package
         "opendaylight",          # Missing opendaylight repo
         "ovsdpdk",               # Not supported on CentOS
-        "sensu-base",            # Dropped by CentOS
         "tgtd",                  # Not supported on CentOS 8
     },
 
@@ -150,7 +149,6 @@
         "opendaylight",  # no binary package
         "ovsdpdk",
         "qdrouterd",
-        "sensu-base",
     },
 
     'ubuntu': {
@@ -159,11 +157,6 @@
 
     'ubuntu+aarch64': {
         "kibana",        # no binary package
-        "sensu-base",    # no binary package
-    },
-
-    'ubuntu+ppc64le': {
-        "sensu-base",    # no binary package
     },
 
     'centos+aarch64': {