v2.28: Azure Repository Storage

Bug Fixes:

* Fix restore --force acting like --force --delta. This caused restore to replace files based on timestamp and size rather than overwriting, which meant some files that should have been updated were left unchanged. Normal restore and restore --delta were not affected by this issue. (Reviewed by Cynthia Shang.)

Features:

* Azure support for repository storage. (Reviewed by Cynthia Shang, Don Seiler.)
* Add expire-auto option. This allows automatic expiration after a successful backup to be disabled. (Contributed by Stefan Fercot. Reviewed by Cynthia Shang, David Steele.)

Improvements:

* Asynchronous S3 multipart upload. (Reviewed by Stephen Frost.)
* Automatic retry for backup, restore, archive-get, and archive-push. (Reviewed by Cynthia Shang.)
* Disable query parallelism in PostgreSQL sessions used for backup control. (Reviewed by Stefan Fercot.)
* PostgreSQL 13 beta2 support. Changes to the control/catalog/WAL versions in subsequent betas may break compatibility but pgBackRest will be updated with each release to keep pace.
* Improve handling of invalid HTTP response status. (Reviewed by Cynthia Shang.)
* Improve error when pg1-path option missing for archive-get command. (Reviewed by Cynthia Shang.)
* Add hint when checksum delta is enabled after a timeline switch. (Reviewed by Matt Bunter, Cynthia Shang.)
* Use PostgreSQL instead of postmaster where appropriate. (Reviewed by Cynthia Shang.)

Documentation Bug Fixes:

* Fix incorrect example for repo-retention-full-type option. (Reported by Höseyin Sönmez.)
* Remove internal commands from HTML and man command references. (Reported by Cynthia Shang.)

Documentation Improvements:

* Update PostgreSQL versions used to build user guides. Also add version ranges to indicate that a user guide is accurate for a range of PostgreSQL versions even if it was built for a specific version. (Reviewed by Stephen Frost.)
* Update FAQ for expiring a specific backup set. (Contributed by Cynthia Shang. Reviewed by David Steele.)
* Update FAQ to clarify default PITR behavior. (Contributed by Cynthia Shang. Reviewed by David Steele.)

test/code-count/file-type.yaml

@@ -799,14 +799,6 @@ src/common/io/handleWrite.h:
   class: core
   type: c/h
 
-src/common/io/http/cache.c:
-  class: core
-  type: c
-
-src/common/io/http/cache.h:
-  class: core
-  type: c/h
-
 src/common/io/http/client.c:
   class: core
   type: c
@@ -839,6 +831,30 @@ src/common/io/http/query.h:
   class: core
   type: c/h
 
+src/common/io/http/request.c:
+  class: core
+  type: c
+
+src/common/io/http/request.h:
+  class: core
+  type: c/h
+
+src/common/io/http/response.c:
+  class: core
+  type: c
+
+src/common/io/http/response.h:
+  class: core
+  type: c/h
+
+src/common/io/http/session.c:
+  class: core
+  type: c
+
+src/common/io/http/session.h:
+  class: core
+  type: c/h
+
 src/common/io/io.c:
   class: core
   type: c
@@ -1371,6 +1387,34 @@ src/protocol/server.h:
   class: core
   type: c/h
 
+src/storage/azure/read.c:
+  class: core
+  type: c
+
+src/storage/azure/read.h:
+  class: core
+  type: c/h
+
+src/storage/azure/storage.c:
+  class: core
+  type: c
+
+src/storage/azure/storage.h:
+  class: core
+  type: c/h
+
+src/storage/azure/storage.intern.h:
+  class: core
+  type: c/h
+
+src/storage/azure/write.c:
+  class: core
+  type: c
+
+src/storage/azure/write.h:
+  class: core
+  type: c/h
+
 src/storage/cifs/storage.c:
   class: core
   type: c
@@ -1651,6 +1695,10 @@ test/lib/pgBackRestTest/Env/ExpireEnvTest.pm:
   class: test/harness
   type: perl
 
+test/lib/pgBackRestTest/Env/Host/HostAzureTest.pm:
+  class: test/harness
+  type: perl
+
 test/lib/pgBackRestTest/Env/Host/HostBackupTest.pm:
   class: test/harness
   type: perl
@@ -2051,6 +2099,10 @@ test/src/module/protocol/protocolTest.c:
   class: test/module
   type: c
 
+test/src/module/storage/azureTest.c:
+  class: test/module
+  type: c
+
 test/src/module/storage/cifsTest.c:
   class: test/module
   type: c