Convert README from Markdown to ReStructured Text and use as longdesc (#22330)

* Convert README from Markdown to ReStructured Text and use as longdesc

Discussion in #13758 led to deciding to switch README to rst and having
setup.py consume it as the long_description.

* Fix long string in setup.py for pep8 compliance

* Open README.rst as read-only

* Update usages of root README.md to README.rst

Unsure about the file ./packaging/debian/docs as it (only) contains the
text README.md. I believe it's referencing ./packaging/debian/README.md
but maybe someone who knows debian packaging could review it?

* Pick up fixes that had been merged into README.md after the initial conversion to rst

packaging/arch/PKGBUILD

@@ -47,7 +47,7 @@ package() {
 
   install -Dm644 examples/ansible.cfg $pkgdir/etc/ansible/ansible.cfg
 
-  install -Dm644 README.md $pkgdir/usr/share/doc/ansible/README.md
+  install -Dm644 README.rst $pkgdir/usr/share/doc/ansible/README.rst
   install -Dm644 COPYING $pkgdir/usr/share/doc/ansible/COPYING
   install -Dm644 CHANGELOG.md $pkgdir/usr/share/doc/ansible/CHANGELOG.md
 

packaging/macports/sysutils/ansible/Portfile

@@ -45,7 +45,7 @@ patch {
 
 post-destroot {
   # documentation and examples
-  xinstall -m 644 -W ${worksrcpath} README.md CHANGELOG.md CONTRIBUTING.md COPYING  \
+  xinstall -m 644 -W ${worksrcpath} README.rst CHANGELOG.md CONTRIBUTING.md COPYING  \
     ${destroot}${prefix}/share/doc/${name}
 
   xinstall -m 755 -d ${destroot}${prefix}/share/doc/examples

packaging/rpm/ansible.spec

@@ -131,7 +131,7 @@ rm -rf %{buildroot}
 %{_bindir}/ansible*
 %dir %{_datadir}/ansible
 %config(noreplace) %{_sysconfdir}/ansible
-%doc README.md PKG-INFO COPYING CHANGELOG.md
+%doc README.rst PKG-INFO COPYING CHANGELOG.md
 %doc %{_mandir}/man1/ansible*
 
 %changelog