add local-url-aware adapter/repository for locale repository with possible download link (file://) for local development systems (no need to generate a downloadURL for every getUrl())
FIX: S3 overwrite option wor downlod_url with %s replacement for key

* add UrlAware Interface for Adapter
* add ctime(), atime(), contentType(), append(), downloadFile()
* change download/upload to pull/push
* optimize keys() ($prefix, $withDirectoryFlag)
* add uri-handling (bnrepo://REPONAME/KEY) for Linker and generation in repo
* add tests for new functions