Update OrderValidator and create DevUtils contract

[abandeali1]

Description

• Renames OrderValidator to OrderValidationUtils for clarity
• Adds signature checking to OrderValidationUtils
• Refactors OrderValidationUtils to use logic from LibAssetData
• Cosmetic changes to LibAssetData
• Creates a top level DevUtils contract that will inherit all pure and view functions that are not in the core contracts

TODOs for a later PR:

• Many of the DevUtils tests should be moved to the asset-proxy package
• Add a remainingFillableAmount to getOrderAndTraderInfo
• Move DevUtils out into its own package

Testing instructions

Types of changes

Checklist:

• Prefix PR title with [WIP] if necessary.
• Add tests to cover changes as needed.
• Update documentation as needed.
• Add new entries to the relevant CHANGELOG.jsons.

[coveralls]

Coverage increased (+0.007%) to 83.679% when pulling 066f3bb on feat/contracts/dev-utils into cf04062 on development.

[dorothy-zbornak]

One bug, but looks good otherwise!