Enable multiple confirmation count values in chain params

[lumtis]

We currently have a single confirmation_count used per chain to determine if a tx is confirmed on a chain.

Under some circumstances, the value can be different:

• between inbound and outbound
• if we want to enable fast observation and fewer confirmation (although we might still want to have a different value per chain, 1 could be a completely unusable value for some networks while acceptable for some other)

Considered change

• For backward compatibility, keeps confirmation_count, this value would be used as a secure fallback on all networks (so would remain the same as currently)
• Determine and implement other fields

Example of other fields

• safe_inbound_confirmation_count
• fast_inbound_confirmation_count
• safe_outbound_confirmation_count
• fast_outbound_confirmation_count

[lumtis]

TODO: add a migration script setting for all chains the same values as the current confirmation_count