ceph-fuse: add connection args parsing support for libfuse > 3.0

ceph-fuse: add connection args parsing support for libfuse > 3.0

Since 3.0 some options are moved to connection part.

The following options are recognized and should be parsed and
applied to the connection:

    -o max_write=N         sets conn->max_write
    -o max_readahead=N     sets conn->max_readahead
    -o max_background=N    sets conn->max_background
    -o congestion_threshold=N  sets conn->congestion_threshold
    -o async_read          sets FUSE_CAP_ASYNC_READ in conn->want
    -o sync_read           unsets FUSE_CAP_ASYNC_READ in conn->want
    -o atomic_o_trunc      sets FUSE_CAP_ATOMIC_O_TRUNC in conn->want
    -o no_remote_lock      Equivalent to -o no_remote_flock,no_remote_posix_lock
    -o no_remote_flock     Unsets FUSE_CAP_FLOCK_LOCKS in conn->want
    -o no_remote_posix_lock  Unsets FUSE_CAP_POSIX_LOCKS in conn->want
    -o [no_]splice_write     (un-)sets FUSE_CAP_SPLICE_WRITE in conn->want
    -o [no_]splice_move      (un-)sets FUSE_CAP_SPLICE_MOVE in conn->want
    -o [no_]splice_read      (un-)sets FUSE_CAP_SPLICE_READ in conn->want
    -o [no_]auto_inval_data  (un-)sets FUSE_CAP_AUTO_INVAL_DATA in conn->want
    -o readdirplus=no        unsets FUSE_CAP_READDIRPLUS in conn->want
    -o readdirplus=yes       sets FUSE_CAP_READDIRPLUS and unsets
                             FUSE_CAP_READDIRPLUS_AUTO in conn->want
    -o readdirplus=auto      sets FUSE_CAP_READDIRPLUS and
                             FUSE_CAP_READDIRPLUS_AUTO in conn->want
    -o [no_]async_dio        (un-)sets FUSE_CAP_ASYNC_DIO in conn->want
    -o [no_]writeback_cache  (un-)sets FUSE_CAP_WRITEBACK_CACHE in conn->want
    -o time_gran=N           sets conn->time_gran

Fixes: https://tracker.ceph.com/issues/45267
Signed-off-by: Xiubo Li <xiubli@redhat.com>