SO: refactor place_closer_order allow_partial

[bitphage]

When cancelling a dust order and placing closer opposite order need to set own asset limiter to avail balance. allow_partial=True doesn't solves the problem when sides are massively imbalanced because allow_partial=True still has a soft limit.

Tets failing: test_allocate_asset_dust_order()

[bitphage]

Also when placing closer order when only one order needed to reach target spread, allow_partial=True also used. Probably need to remove soft limit imposed by allow_partial=True: balance > order['base']['amount'] * self.partial_fill_threshold), and probably remove bundling when bootstrap is off.

[bitphage]

test_allocate_asset_dust_order() is no longer indicates an issue, a separate test should be written.