Expose New call_raw API that permits MultiCalls without Detokenization

[3lpsy]

Motivation

Multicall's add_call method is capped at 16 calls due to detokenization (tuple) contraints. Such a cap may force users to make more calls than necessary.

References: #900

Solution

Expose a new call_raw method on the MultiCall interface that skips detokenization. The call method can then wrap call_raw to avoid code duplication and add in the detokenization.

Additional Notes

• While current tests should ensure no regressions for call, only a simple test was added for call_raw. This may need to be improved.
• The 16 call limit panic is moved from add_call to call. As it's a panic, it is not likely to cause issues in current deployments; however, it may be worth pointing out in Changelog in case anyone relied upon it.
• The test cases for multicall_aggregate did not appear to be compatible with ganache ^7.0.0 as they assumed default accounts were seeded with 100 ether, not 1000 ether. Changes were made to spawn to accommodate this
• Documentation was added / modified for call_raw and call; however, formatting still needs to be checked

PR Checklist

• Added Tests
• Added Documentation
• Updated the changelog

[roynalnaruto]

Looks good to me!

[gakonst]

nice work!