New Website: Remove Old Content [2/3] (apache#15885)

* Adding new website files

Co-authored-by: Thomas Delteil <[email protected]>
Co-authored-by: Aaron Markham <[email protected]>

* removing old content

Co-authored-by: Thomas Delteil <[email protected]>
Co-authored-by: Aaron Markham <[email protected]>

* add license header

* fixing links and url + css

* fixing tutorials

* exclude python_docs folder when building prod site

This allows things to coexist until a following PR deletes this file.

* license header fixes

* exclude static site from license header check

* exclude static site and sphinx theme

* exclude static_site and cpp_docs from sphinx

* add licenses and excludes

* fix headers

* restore file for legacy builds

* empty commit to trigger CI

* update submodule to correct one

* delete website check

* add placeholder website check

* add placeholder website check, for reals this time

* trigger CI

* trigger PR

ci/jenkins/Jenkinsfile_website

@@ -33,13 +33,10 @@ utils.assign_node_labels(utility: 'utility', linux_cpu: 'mxnetlinux-cpu')
 
 utils.main_wrapper(
 core_logic: {
-  utils.parallel_stage('Build', [
-    custom_steps.compile_unix_cpu_openblas()
+  utils.parallel_stage('Placeholder', [
+    // Do nothing
   ])
 
-  utils.parallel_stage('Deploy', [
-    custom_steps.docs_website(),
-  ])
 }
 ,
 failure_handler: {