feat: implement no sandwiching using share burning and minting

[jmonteer]

Description

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context. List any dependencies that are required for this change.

Fixes # (issue)

Checklist

• [ ] I have run vyper and solidity linting
• [ ] I have run the tests on my machine
• [ ] I have followed commitlint guidelines
• [ ] I have rebased my changes to the latest version of the main branch

[jmonteer]

pending:

• insta burn shares when losses are reported
• tests

[jmonteer]

pending:

• tests
• constructor setup

[jmonteer]

pending:

• more tests
• precision in share burning
• constructor setup (immutable)

[jmonteer]

pending tests: no existing buffer:

• report gain, no fees, no refunds (should keep pps)
• report gain, fees, no refunds (should keep pps if fees < gain, reduce pps if fees > gain)
• report gain, no fees, refunds (should keep pps and lock both gain and refunds)
• report gain, fees, refunds (should keep pps if gain + refunds >= loss, decrease pps elsewhere)
• report loss, no fees, no refunds (should decrease pps)
• report loss, fees, no refunds (should decrease pps)
• report loss, no fees, refunds (should keep pps if refunds >= loss, reduce it otherwise)
• report loss, fees, refunds (should keep pps if loss + fees <= refunds, reduce it otherwise)

test the same with an existing buffer (i.e. previously locked shares) (pps should not change if there's enough buffer to cover fees + loss) AND

• report loss that is fully covered by existing buffer (should keep pps)
• report loss not fully covered by existing buffer (should decrease pps)