feat(core): update read_zkey with new_unchecked

[vivianjeng]

According to #25 (comment)

loading zkey time	ark-zkey	with new_unchecked
multiplier2	872.00ns	1.21µs
keccak256	115.82s	1.56s

[oskarth]

I wonder if we want to combine ark-zkey with this? Because with ark-zkey we get 50% file size reduction due to point compression.

[oskarth]

do we have to remove the ARKZKEY stuff you think? or is this preferable?

thinking mostly about space savings which are quite significant

[oskarth]

If we remove/don't update arkzkey stuff, could we create an issue explaining problem and current state? So even if we don't do it now we can introduce this for arkzkey too

[vivianjeng]

I think we can create the issue to describe the situation

I think arkzkey is still doable without the current serialization/deserialization
like in circom-compat
https://github.com/arkworks-rs/circom-compat/blob/170b10fc9ed182b5f72ecf379033dda023d0bf07/src/zkey.rs#L328

but I am figuring out what is the correct way to serialize/deserialize

[vivianjeng]

Create an issue here
#130