Feature request: controlled sealing

[bobdubois]

Currently the only sensible way to control the amount of deals per hour or day that hits the sealing pipeline is:

• import X amount of deals and kill spader OR
• limit the dir_size variable to the size of the deals the sealing pipeline can handle

A more flexible way to control the amount of deals per hour or per day would be favorable. I know how many deals my pipeline can process per hour and it would be useful to feed it just enough so there is a continuous flow of deals at maximum throughput for the miner without choking it.

[LexLuthr]

@bobdubois Can you please test the new branch in #2? Please make sure to let the current deals complete and then use a new directory to test.

[bobdubois]

pulled the code and running spade.py with the new commit.
No deals incoming (yet) because of datacap issues on the tenant I see eligible deals for.