Merge branch 'changelog/58'

* changelog/58:
  Add changelog for 58

CHANGELOG.rst

+#########
+Changelog
+#########
+
+[58] - 2021-07-31
+=================
+
+Added
+-----
+
+- Add README.rst and CONTRIBUTING.rst
+- Add editorconfig integration
+- Add GitLab CI integration
+
+Changed
+-------
+
+- Adapt Makefile to new repository layout and only test and install files that are part of mkinitcpio-archiso
+- Fix formatting of hooks and scripts according to shfmt