Re-evaluate existential deposit & cross-chain asset minimal balance

[Dinonard]

Existential deposits on Astar & Shiden networks are very low, so much as they become irrelevant.
Same is for the minimal balance of cross-chain assets which are marked as sufficient.

This should be revised in the future, and aligned more with the rent fee amounts.

[Dinonard]

Potentially a lot of work resulting in breaking changes, would require a lot of coordination.
Benefits for network at this state are basically none.