Make v19.2 visible on Release Support Policy page

Fixes DOC-15195

Summary of changes:

- Add back v19.2 to versions.csv - this fixes the 'Release Support
  Policy' page

- Add back v19.2.0 to releases.yml (and only that version) - this fixes
  the 'Unsupported Versions' page

- Add back simplified releases/v19.2.md - this is linked to from the
  'Unsupported versions' page

Author: rmloveland

src/current/_data/releases.yml

@@ -1798,6 +1798,16 @@
   source: true
   previous_release: v19.1.10
 
+- release_name: v19.2.0
+  major_version: v19.2
+  release_date: '2019-11-12'
+  release_type: Production
+  go_version: go1.12.12
+  sha: 338deb20a6e34750635d6be5385498d5871ff68c
+  windows: true
+  docker:
+    docker_image: cockroachdb/cockroach
+  source: true
 
 - release_name: v20.2.0-alpha.2
   major_version: v20.2

src/current/_data/versions.csv

@@ -4,6 +4,7 @@ v1.1,2017-10-12,2018-10-12,2019-04-12,N/A,N/A,N/A,N/A,N/A,v1.0,release-1.1,2024-
 v2.0,2018-04-04,2019-04-04,2019-10-04,N/A,N/A,N/A,N/A,N/A,v1.1,release-2.0,2024-01-01
 v2.1,2018-10-30,2019-10-30,2020-04-30,N/A,N/A,N/A,N/A,N/A,v2.0,release-2.1,2024-01-01
 v19.1,2019-04-30,2020-04-30,2020-10-30,N/A,N/A,N/A,N/A,N/A,v2.1,release-19.1,2024-01-01
+v19.2,2019-11-12,2020-11-12,2021-05-12,N/A,N/A,N/A,N/A,N/A,v19.1,release-19.2,2024-01-01
 v20.1,2020-05-12,2021-05-12,2021-11-12,N/A,N/A,N/A,N/A,N/A,v19.1,release-20.1,2025-05-12
 v20.2,2020-11-10,2021-11-10,2022-05-10,N/A,N/A,N/A,N/A,N/A,v20.1,release-20.2,2025-05-12
 v21.1,2021-05-18,2022-05-18,2022-11-18,N/A,N/A,N/A,N/A,N/A,v20.2,release-21.1,2025-05-18

src/current/releases/v19.2.md

@@ -0,0 +1,13 @@
+---
+title: What's New in v19.2
+toc: true
+toc_not_nested: true
+summary: Additions and changes in CockroachDB version v19.2 since version v19.1
+major_version: v19.2
+docs_area: releases
+keywords: gin, gin index, gin indexes, inverted index, inverted indexes, accelerated index, accelerated indexes
+---
+
+<a name="v19-2-0"></a>
+
+This release is no longer supported. For more information, see our [Release support policy]({% link releases/release-support-policy.md %}).