TICK_SIZE - waves.exchange

[ttodua]

this PR updates the too old implementation of complex custom precision manipulations (the last edits were 4 years old, probably the Precise class was not developed well by that time).

This PR solves:

1. moves exchange from DECIMAL_PLACES to TICK_SIZE.

2. there were many scattered methods in the implementation: customPriceToPrecision, customAmountToPrecision, customCurrencyToPrecision, fromPrecision, toPrecision, currencyFromPrecision, priceFromPrecision ... 🤯 .

Now I've implemented the simpler : fromReal / toReal methods (for market amount & price and currency amount)

3. fixes withdraw, createOrder and few others. I've tested all methods (public & private) and all seems to be working well.

[ttodua]

@kroitor I've run private tests (no issues) and also made a test order (works as expected).

[ttodua]

@carlosmiei passes