manuals: split dev-manual/common-tasks.rst

A 500 KB source file is always harder to manage,
and can have section title conflicts.

So, the "Common Tasks" document is gone and all
its constituents are moved up one level.
You now have 40 chapters in the Development Tasks Manual.

(From yocto-docs rev: 8a45bc469411410020b8e688c137395fcaf3761b)

Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/dev-manual/disk-space.rst

@@ -0,0 +1,40 @@
+.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
+
+Conserving Disk Space
+*********************
+
+Conserving Disk Space During Builds
+===================================
+
+To help conserve disk space during builds, you can add the following
+statement to your project's ``local.conf`` configuration file found in
+the :term:`Build Directory`::
+
+   INHERIT += "rm_work"
+
+Adding this statement deletes the work directory used for
+building a recipe once the recipe is built. For more information on
+"rm_work", see the
+:ref:`rm_work <ref-classes-rm-work>` class in the
+Yocto Project Reference Manual.
+
+Purging Duplicate Shared State Cache Files
+==========================================
+
+After multiple build iterations, the Shared State (sstate) cache can contain
+duplicate cache files for a given package, while only the most recent one
+is likely to be reusable. The following command purges all but the
+newest sstate cache file for each package::
+
+   sstate-cache-management.sh --remove-duplicated --cache-dir=build/sstate-cache
+
+This command will ask you to confirm the deletions it identifies.
+
+.. note::
+
+   The duplicated sstate cache files of one package must have the same
+   architecture, which means that sstate cache files with multiple
+   architectures are not considered as duplicate.
+
+Run ``sstate-cache-management.sh`` for more details about this script.
+