[SC-1165] Community resolvers logic

[zZoMROT]

Concerning gasUsed in postInteraction calldata using for backward compatibility:

# use resolverFeeEnabled() 2 times
| ResolverMock · settleOrders    · 122098 · 132917 · 125704 │
| Settlement   · postInteraction ·  28203 ·  32541 ·  31448 │

# use bool feeEnabled variable inside unchecked block
| ResolverMock · settleOrders    · 122073 · 132725 · 125624 │
| Settlement   · postInteraction ·  28160 ·  32355 ·  31298 │

# use bool feeEnabled variable outside unchecked block
| ResolverMock · settleOrders    · 122070 · 132710 · 125617 │
| Settlement   · postInteraction ·  28151 ·  32358 ·  31298 │

# use extraDataShift variable instead of cut extraData after feeEnabled check
| ResolverMock · settleOrders    · 122241 · 132948 · 125810 │
| Settlement   · postInteraction ·  28345 ·  32558 ·  31496 │

So, the best way is use bool feeEnabled variable outside unchecked block.