Enhancement: Add the webdav service

Tags: webdav

 * Enhancement - Add version command: [#226](https://github.com/owncloud/product/issues/226)
 * Bugfix - Build docker images with alpine:latest instead of alpine:edge: [#22](https://github.com/owncloud/ocis-webdav/pull/22)
 * Change Change status not found on missing thumbnail: [#20](https://github.com/owncloud/ocis-webdav/issues/20)
 * Change - Initial release of basic version: [#1](https://github.com/owncloud/ocis-webdav/issues/1)
 * Change - Update ocis-pkg to version 2.2.0: [#16](https://github.com/owncloud/ocis-webdav/issues/16)
 * Enhancement - Configuration: [#14](https://github.com/owncloud/ocis-webdav/pull/14)
 * Enhancement - Implement preview API: [#13](https://github.com/owncloud/ocis-webdav/pull/13)

 https://github.com/owncloud/product/issues/244
