Add base Dropdown and Dropdown.Menu components

[pixelbandito]

No description provided.

[mdespuits]

@pixelbandito One thing you should change in this PR is to change the release script. We actually don't want to add a yarn tag with the version. So you'll need to change this:

diff --git a/package.json b/package.json
index 807908d..47ad682 100644
--- a/package.json
+++ b/package.json
@@ -55,7 +55,7 @@
     "prepublish": "yarn test && yarn build",
     "predeploy": "cd example && yarn install && yarn run build",
     "postpublish": "git tag v$npm_package_version && git push --tags && echo \"Successfully released version $npm_pa
-    "release": "yarn publish . --tag $npm_package_version --no-git-tag-version",
+    "release": "yarn publish --no-git-tag-version",
     "deploy": "gh-pages -d example/build",
     "storybook": "start-storybook -p 9009",
     "build-storybook": "build-storybook"

[pixelbandito]

@mdespuits I did that thing you asked for ^

[chelshaw]

👏