delete: added initial implementation of the backrunner background deletion process
buckets: added buckets delete metadata and common buckets constants
proxy: use custom string as delete index, use external buckets constants, fixed returned get/update/delete URL schema
delete: implemented bucket metadata read, 'delete' index iteration and deletions of the objects whose 'deletion' time had passed
Added gitignore and bucket example jsons
gitignore: import gitignore file