Bluetooth: Classic: SDP: Improve SDP discover

Extend the function `bt_sdp_discover` to support service search
transaction and service attribute transaction.

Improve the `session->rec_buf`. If the net buffer cannot be allocated
from the channel, disconnect the SDP session.

Set the `MaximumAttributeByteCount` of the request
`SDP_SERVICE_SEARCH_ATTR_REQ` with the tail room of `session->rec_buf`.

Set the `MaximumAttributeByteCount` of the request `SDP_SERVICE_ATTR_REQ`
with the tail room of `session->rec_buf`.

Set the `MaximumServiceRecordCount` of the request
`SDP_SERVICE_SEARCH_REQ` according to the tail room of
`session->rec_buf`.

Handle the response code `SDP_SERVICE_SEARCH_RSP`, and
`SDP_SERVICE_ATTR_RSP`.

Handle the error `SDP_ERROR_RSP`. Start the next SDP discovery if the
error received.

If there no more request, disconnect the session.

If the request cannot be sent, start the next SDP discovery.

Signed-off-by: Lyle Zhu <lyle.zhu@nxp.com>