Search Roadmap and Architecture (#4030)

* search documentation and roadmap

* fixup

* add link to architecture issue

* formatting

* add nav to mkdocs yaml and microsite sidebar

* use backstage search instead of backstage global search

* add file extension to app_config

* Update docs/features/search/README.md

Co-authored-by: Himanshu Mishra <himanshu@orkohunter.net>

* replace Big Picture with Architecture

* search architecture wip

* changes to architecture and documentation to it

* update used user profiles according to the glossary

* prettier ignore description

* clarify architecture bullet points with examples

Co-authored-by: Himanshu Mishra <himanshu@orkohunter.net>

microsite/sidebars.json

@@ -72,6 +72,14 @@
           "features/software-templates/extending/extending-preparer"
         ]
       },
+      {
+        "type": "subcategory",
+        "label": "Backstage Search",
+        "ids": [
+          "features/search/search-overview",
+          "features/search/architecture"
+        ]
+      },
       {
         "type": "subcategory",
         "label": "TechDocs",