bpf, docs: Libbpf overview documentation

This patch documents overview of libbpf, including its features for
developing BPF programs.
Signed-off-by: Sreevani Sreejith <ssreevani@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230315195405.2051559-1-ssreevani@meta.com

Documentation/bpf/libbpf/index.rst

@@ -2,23 +2,32 @@
 
 .. _libbpf:
 
+======
 libbpf
 ======
 
+If you are looking to develop BPF applications using the libbpf library, this
+directory contains important documentation that you should read.
+
+To get started, it is recommended to begin with the :doc:`libbpf Overview
+<libbpf_overview>` document, which provides a high-level understanding of the
+libbpf APIs and their usage. This will give you a solid foundation to start
+exploring and utilizing the various features of libbpf to develop your BPF
+applications.
+
 .. toctree::
    :maxdepth: 1
 
+   libbpf_overview
    API Documentation <https://libbpf.readthedocs.io/en/latest/api.html>
    program_types
    libbpf_naming_convention
    libbpf_build
 
-This is documentation for libbpf, a userspace library for loading and
-interacting with bpf programs.
 
-All general BPF questions, including kernel functionality, libbpf APIs and
-their application, should be sent to bpf@vger.kernel.org mailing list.
-You can `subscribe <http://vger.kernel.org/vger-lists.html#bpf>`_ to the
-mailing list search its `archive <https://lore.kernel.org/bpf/>`_.
-Please search the archive before asking new questions. It very well might
-be that this was already addressed or answered before.
+All general BPF questions, including kernel functionality, libbpf APIs and their
+application, should be sent to bpf@vger.kernel.org mailing list.  You can
+`subscribe <http://vger.kernel.org/vger-lists.html#bpf>`_ to the mailing list
+search its `archive <https://lore.kernel.org/bpf/>`_.  Please search the archive
+before asking new questions. It may be that this was already addressed or
+answered before.