Remove index functions

[KyGost]

Requires: #156

Indexes should be stored as tables, MultiSQL should manage via scan_pk_range for index tables

[KyGost]

For this to work with dupes, PK would need to be double sized...

[KyGost]

Maybe be okay with requiring a squeeze into half types...?

[KyGost]

Start with only unique indexes

[KyGost]

Multiple value and long type (eg. text) indexes wouldn't work with squeezing.

What is gained by forcing [U8; 8]/U64?