Change default epoch parameters in the Mana Calculator

[oliviasaa]

For now, this is not relevant, but once the network is launched, the default settings for initial and final epochs should be
current epoch and current epoch + 9
instead of 1 and 10

(where current epoch is either the exact epoch from the network or at least something close to it)

This is important because of the decreasing rewards; we could find ourselves in a situation where people use the default epoch settings and expect to get more rewards than what they'll actually get.