docs: Add mkdocs support to render static documentation site on GitHub (#3070)

* docs: Add `mkdocs` support to render static documentation site on GitHub

* fix: Correct mis-spelled file name

mkdocs.yml

@@ -0,0 +1,65 @@
+site_name: Terraform AWS EKS
+docs_dir: docs/
+site_url: https://terraform-aws-modules/terraform-aws-eks/
+repo_name: terraform-aws-eks
+repo_url: https://github.com/terraform-aws-modules/terraform-aws-eks
+
+theme:
+  name: material
+  logo: assets/terraform-aws.png
+  favicon: assets/logo.png
+  font:
+    text: ember
+  palette:
+    primary: deep purple
+    accent: indgo
+  icon:
+    repo: fontawesome/brands/github
+    admonition:
+      note: octicons/tag-16
+      abstract: octicons/checklist-16
+      info: octicons/info-16
+      tip: octicons/squirrel-16
+      success: octicons/check-16
+      question: octicons/question-16
+      warning: octicons/alert-16
+      failure: octicons/x-circle-16
+      danger: octicons/zap-16
+      bug: octicons/bug-16
+      example: octicons/beaker-16
+      quote: octicons/quote-16
+  features:
+    - navigation.tabs.sticky
+  highlightjs: true
+  hljs_languages:
+    - yaml
+    - json
+
+plugins:
+  - include-markdown
+  - search:
+      lang:
+        - en
+  - awesome-pages
+
+extra:
+  version:
+    provider: mike
+
+markdown_extensions:
+  - attr_list
+  - admonition
+  - codehilite
+  - footnotes
+  - md_in_html
+  - pymdownx.critic
+  - pymdownx.details
+  - pymdownx.highlight:
+      anchor_linenums: true
+      line_spans: __span
+      pygments_lang_class: true
+  - pymdownx.inlinehilite
+  - pymdownx.snippets
+  - pymdownx.superfences
+  - toc:
+      permalink: true