[FR] Merge iCKB Utils Epoch features into CCC

[phroi]

From #261

• [@phroi] please take a look at iCKB/Utils and check out what makes sense to bring into CCC

• [@Hanssen0] I'm curious about modifications on Epoch [...] It looks like it's possible to port them to CCC's codebase.

• [@phroi] Epoch would be nice, I worked quite a bit to reach that level. Only issue is that maybe it uses GCD too much. Maybe not all people are comfortable with that. If you add Epoch, then GCD should be added too.

• [@Hanssen0] GCD is fine.

[phroi]

iCKB/Utils Epoch is implemented as a class, while CCC Epoch is implemented as an Array: type Epoch = [Num, Num, Num]

Class representation is useful to group all the Epoch utilities such as:

• Normalization of index / length in Epoch.from
• Hex conversions
• Epoch comparisons
• Epoch addition
• Epoch subtraction
• Unix conversion

How do your propose to reconcile the difference between Class and Array representation?

Love & Peace, Phroi %10

[Hanssen0]

I think we should be able to switch to the class representation while maintaining compatibility.

https://github.com/ethers-io/ethers.js/blob/9fd9d41d017a5e3b329aca47c79786e69cd40b99/src.ts/abi/coders/abstract-coder.ts#L68

might help.