[docs] Migrate docs from AsciiDoc to Markdown (#2221)

* delete asciidoc files

* add migrated files

* clean up cross-repo links

* apply suggestions from code review

Co-authored-by: Riccardo Magliocchetti <[email protected]>

* fix external links that should contain .html

* update lambda support page

* add code annotation

* rename files that contain a period

* clean up

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Co-authored-by: Riccardo Magliocchetti <[email protected]>

Author: colleenmcginnis