Documentation integration (#4653)

* Add documentation under docs/ directory

* Add CI workflow for mkdocs configuration checking

* Add documentation issue template

* update pip-tools?

* Update .gitignore files

* Fix .gitignore rules

* Improve release notes page

* remove references to old repo

docs/docs/settings/export.md

@@ -0,0 +1,17 @@
+---
+title: Exporting Data
+---
+
+## Exporting Data
+
+The Admin Interface provides powerful data exporting capability. When displaying a list of items which support exporting (e.g. Part objects), select the "Export" button from the top-right corner:
+
+{% with id="export", url="admin/export.png", description="Data export" %}
+{% include 'img.html' %}
+{% endwith %}
+
+Multiple data formats are supported for exported data:
+
+{% with id="formats", url="admin/formats.png", description="Data formats" %}
+{% include 'img.html' %}
+{% endwith %}