Max profit to quit/hard cutoff - to support accounts - BUG

[drew2323]

Enable max profit to quit functionality (StrategyClassicSL.py - function stop_when_max_profit_loss) to be configured also on level of each account (currently now only overall for all accounts).

Design a notation in stratvars, something along these lines:

max_rel_profit_to_quit = [0.8, 0.3]
max_rel_profit_to_quit = [ACCOUNT1, ACCOUNT2]

Same with max loss (hard cutoff) max_sum_loss_to_quit = -500 - currently if the max loss is reached when closing a trade - it just shuts off regardless if there is another (maybe profitable) trade active on the different account - which causes that strategy shuts down leaving a trade active overnight.

Note: maybe it could be solved by existing directive hard_cutoff = false - doesnt quit rightaway but just blocks any new ENTRIES