Renaming refused on hosted drives because encrypted names and contents are
bound to their path. The encrypting client now renames itself: readable
files keep s3d's server-side copy, the rest are decrypted and encrypted again
for their new place. A drive with shared folders or links is not renamed,
since its rules belong to the old name.
Free space is forwarded to the server, whose s3d answers for its own
folder, instead of reporting nothing. space.js now builds on sia-account.js,
so BLAKE2b and the indexer request signing exist once.
S3 has no rename, so files, folders and drives kept the name they were
made with. s3d copies objects in its own database (the copy points at
the same data on Sia), so a rename is a copy to the new name and a
delete of the old: quick, and it uses no extra storage. A drive rename
makes a new bucket, moves every file, rebuilds public access for the new
name (a policy names its bucket) and removes the old one. Names that
already exist are refused. Drives on Silent Mode encrypt with keys tied
to each name, so their client gets no rename until it can re-encrypt.
The drives page and Overview now show how much of the Sia account is
used and how much is free. s3d does not report it; the indexer's
GET /account does, signed with the app key s3d registered (read from its
database for this one request, BLAKE2b-256 + Ed25519 as indexd expects).
