Add readthedocs config and conda environment for documentation

Author: jan-janssen

.ci_support/environment-docs.yml

@@ -0,0 +1,6 @@
+channels:
+- conda-forge
+dependencies:
+  - nbsphinx
+  - sphinx
+  - myst-parser

.readthedocs.yml

@@ -0,0 +1,28 @@
+# .readthedocs.yml
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+# Required
+version: 2
+
+build:
+  os: "ubuntu-20.04"
+  tools:
+    python: "mambaforge-4.10"
+
+# Build documentation in the docs/ directory with Sphinx
+sphinx:
+  configuration: docs/source/conf.py
+
+# Optionally build your docs in additional formats such as PDF and ePub
+formats: []
+
+# Install pyiron from conda
+conda:
+  environment: .ci_support/environment-docs.yml
+
+# Optionally set the version of Python and requirements required to build your docs
+python:
+  install:
+    - method: pip
+      path: .