[jsk_data] add wait_timer for timer method

[shmpwk]

As to data_collection_server, wait_service_request for request method was implemented by #1669 .
So I apply it to the other methods such as timer method and all method.

[knorth55]

I think waiting for all method is meaningless because all msgs are received and updated in sync_sub_and_save_cb.
but for timer, it might be useful.

[knorth55]

@shmpwk can you check shmpwk#1 ?

[shmpwk]

@knorth55 You're right. I just tried it for timer and thought that it can be also applied to all.

[shmpwk]

Thank you for the revise.
I fix typo on shmpwk#1 by fac3f9c.
I confirm it works with wait_save_request: true or false and wait_timer: true or false.