propose experimental folder (#632)
propose experimental folder (#632)

* propose experimental folder

* misspell

* update wording

* require experimental note in files

* Update experimental/README.md

Co-authored-by: Armin Ruech <5375d2e98a78036adfbf90c7f7841c3894b65d4b@dynatrace.com>

* Update experimental/README.md

Co-authored-by: Armin Ruech <5375d2e98a78036adfbf90c7f7841c3894b65d4b@dynatrace.com>

* Update experimental/README.md

Co-authored-by: Reiley Yang <30492acf0f6ef8016cbaa2354294f909e563626a@microsoft.com>

Co-authored-by: Armin Ruech <5375d2e98a78036adfbf90c7f7841c3894b65d4b@dynatrace.com>
Co-authored-by: Reiley Yang <30492acf0f6ef8016cbaa2354294f909e563626a@microsoft.com>
open-telemetry/opentelemetry-specification,open-telemetry/opentelemetry-specification