Move .md files to /docs/ (#2832)

* Move most MD files to docs folder

* Update CHANGELOG.md

* Update CHANGELOG.md

* Condense to one samples list

* Delete SAMPLES.md file

Author: corinagum

CHANGELOG.md

@@ -51,6 +51,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 -  Fixes [#2459](https://github.com/microsoft/BotFramework-WebChat/issues/2459). Updated Cognitive Services Speech Services to use latest fetch credentials signature, by [@compulim](https://github.com/compulim) in PR [#2740](https://github.com/microsoft/BotFramework-WebChat/pull/2759)
 -  Fixes [#1673](https://github.com/microsoft/BotFramework-WebChat/issues/1673). Configured suggested action and carousel flippers to blur on click, by [@tdunford](https://github.com/tdurnford) in PR [#2801](https://github.com/microsoft/BotFramework-WebChat/pull/2801)
 -  Fixes [#2822](https://github.com/microsoft/BotFramework-WebChat/issues/2822). Fixed `credentials` should return `authorizationToken` and `subscriptionKey` as string and allow empty LUIS reference grammar ID, by [@compulim](https://github.com/compulim) in PR [#2824](https://github.com/microsoft/BotFramework-WebChat/pull/2824)
+-  Fixes [#2751](https://github.com/microsoft/BotFramework-WebChat/issues/2751). Move documentation to docs folder, by [@corinagum](https://github.com/corinagum) in PR [#2832](https://github.com/microsoft/BotFramework-WebChat/pull/2832)
 
 ### Changed
 
@@ -354,7 +355,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 -  Resolves [#2157](https://github.com/Microsoft/BotFramework-WebChat/issues/2157), added `emitTypingIndicator` action and dispatcher, by [@compulim](https://github.com/compulim), in PR [#2413](https://github.com/microsoft/BotFramework-WebChat/pull/2413)
 -  Resolves [#2307](https://github.com/Microsoft/BotFramework-WebChat/issues/2307). Added options to hide ScrollToEnd button, by [@nt-7](https://github.com/nt-7) in PR [#2332](https://github.com/Microsoft/BotFramework-WebChat/pull/2332)
 -  Added bubble nub and style options, by [@compulim](https://github.com/compulim), in PR [#2137](https://github.com/microsoft/BotFramework-WebChat/pull/2137) and PR [#2487](https://github.com/microsoft/BotFramework-WebChat/pull/2487)
--  Resolves [#1808](https://github.com/microsoft/BotFramework-WebChat/issues/1808). Added documentation on activity types, by [@corinagum](https://github.com/corinagum) in PR [#2228](https://github.com/microsoft/BotFramework-WebChat/pull/2228)
+-  Resolves [#1808](https://github.com/microsoft/BotFramework-WebChat/issues/1808). Added documentation on [activity types](https://github.com/microsoft/BotFramework-WebChat/tree/master/docs/ACTIVITYTYPES.md), by [@corinagum](https://github.com/corinagum) in PR [#2228](https://github.com/microsoft/BotFramework-WebChat/pull/2228)
 -  Added `timestampFormat` option to the default style options and created `AbsoluteTime` component, by [@tdurnford](https://github.com/tdurnford), in PR [#2295](https://github.com/microsoft/BotFramework-WebChat/pull/2295)
 -  `embed`: Added ES5 polyfills and dev server, by [@compulim](https://github.com/compulim), in PR [#2315](https://github.com/microsoft/BotFramework-WebChat/pull/2315)
 -  Resolves [#2380](https://github.com/microsoft/BotFramework-WebChat/issues/2380). Added `botAvatarBackgroundColor` and `userAvatarBackgroundColor` to the default style options, by [@tdurnford](https://github.com/tdurnford) in PR [#2384](https://github.com/microsoft/BotFramework-WebChat/pull/2384)