Pick up ParaView changes with new CI images. Minor ci doc update.

.gitlab/ci/download_superbuild.cmake

@@ -9,13 +9,13 @@ set(data_host "https://data.kitware.com")
 
 # Determine the tarball to download. ci-smtk-ci-developer-{date}-{git-sha}.tar.gz
 if ("$ENV{CMAKE_CONFIGURATION}" MATCHES "vs2019")
-  # 20201124
-  set(file_item "6033ca892fa25629b99c67d8")
-  set(file_hash "55354ae4fbdfb74b1cb09e1535cb855d4bdda8370941ec7f20a6d1f2476fc145bb134d3c6d2eb6dea26168e981051237d880d4fb290a53372405fa5c4e0004f7")
+  # 20210304
+  set(file_item "604117fe2fa25629b9f3a765")
+  set(file_hash "a70a62192456d4f94c33d9d6c632c270a3af8497509e1922e17aa75a3f783e1fcd18caa03a8246000551345eef2c6f4741ee96a9baede7822dab3c1f37c6d7c9")
 elseif ("$ENV{CMAKE_CONFIGURATION}" MATCHES "macos")
-  # 20201124
-  set(file_item "6033cb0a2fa25629b99c68b7")
-  set(file_hash "9f3c39e30ca6dce10d61697d73320c08a3c999cbf28449f6b9472ad9e0fa6e4973863917cae9e1a2b201d74d92df05830607efb760455d41160f0c35cca5857a")
+  # 20210304
+  set(file_item "604117c42fa25629b9f3a673")
+  set(file_hash "f74057d8675f7c3ca690bc851f6121d4824f791d226e97823bf7e4f3b0d1d8d4afab73dc467ac86d32578ffa865cc283b60db5b75f9b572b06a3017ac3658f74")
 else ()
   message(FATAL_ERROR
     "Unknown build to use for the superbuild")