Add Decimal splitting SwiftLint rule

[yaroslavyaroslav]

Working with a large numbers in lib makes it error prone in term of putting wrong dimension, e.g 1_000_000 instead of 10_000_000. Luckily swift allows to use notation above which makes it much clearer to see what exact dimension number have.

So this notation should be forced with appropriate SwiftLint rule.

[JeneaVranceanu]

Looks like this is what you are looking for: https://realm.github.io/SwiftLint/number_separator.html

[JeneaVranceanu]

@yaroslavyaroslav Can this one be closed?