...into pathfinding, monitor and udc epics, since the generic epic
module was already too big.

Now named udcWithdraw, and the previous udcWithdraw is renamed to
udcWithdrawPlan. Also, a small refactoring to check if totalDeposit is
outdated late, right before calling deposit (after approveIfNeeded$).

udcWithdraw phase (after plan) is now a request/success/failure epic.
udcWithdraw.request is handled, dispatches the transaction, wait for it
to be mined and output either success or failure.
If config.autoUdcWithdraw is enabled (default), an epic will watch the
blockchain for plans from us and dispatch the udcWithdraw.request

The former queries the UDC for currently planned withdraws, returning
amount, block in which it becomes available and ready state; the later
is to be called when config.autoUdcWithdraw is false and after plan is
'ready', and interactively performs the last UDC withdraw phase.

- Raiden.udcWithdraw -> Raiden.withdrawFromUDC
- Raiden.planUdcWithdraw -> Raiden.planUDCWithdraw
- config.autoUdcWithdraw -> config.autoUDCWithdraw
- 100 -> constants.UDC_WITHDRAW_TIMEOUT