Addressed a front-running vulnerability in the matching engine

[jalextowle]

Description

This PR allows traders to set a counterparty and fee recipient for their trade. This prevents front-running that could violate the trader's intentions. These parameters are optional and will be ignored if they are set to address(0).

[coveralls]

Pull Request Test Coverage Report for Build 12939610278

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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Details

• 6 of 6 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 89.255%

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Totals
Change from base Build 12938071562:	0.02%
Covered Lines:	2924
Relevant Lines:	3276

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💛 - Coveralls

[Sean329]

Talked to Alex offline for some questions wrt this change. The PR looks good