This commit adds the bucket delete and bucket policy functionalities
to the browser.
Part of rewriting the browser code to follow best practices and
guidelines of React (issues #5409 and #5410)
The backend code has been modified by @krishnasrinivas to prevent
issue #4498 from occuring. The relevant changes have been made to the
code according to the latest commit and the unit tests in the backend.
This commit also addresses issue #5449.
