'varint' and 'decimal' scylla types does`t work properly as a maps key.

[illia-li]

gocql data parsing from scylla defines 'varint' scylla type as 'big.Int' go type.
big.Int not compareble.
Not compareble types can`t be as a maps key.
gocql got out of the situation by create pointer on big.Int.
This led to the fact that a maps key - pointer, not a big.Int.
With 'decimal' same situation because gocql defines 'decimal' as inf.Dec go type, which contains big.Int.

[roydahan]

@dkropachev how easy to fix?

[dkropachev]

@dkropachev how easy to fix?

This fix is too complicated, i won't merge it.
I am working on another one, that is less crazy, but still on the line.