Enhancement request for ClickHouse targets: Be able to specify the custom numeric precision and scale for mirrors

[konsta-danyliuk]

Current behaviour

• PeerDBClickHouseScale is hard-coded as 38.

  peerdb/flow/shared/datatypes/numeric.go

  Line 7 in cffcf45

  PeerDBClickHouseScale = 38

• When one tries to get a Postgres unbounded numeric column into ClickHouse, it is converted into Decimal(78, 38) and a user has no control over it.
• This may be a problem when ingesting large numbers from unbounded numeric Postgres columns.

Suggested behaviour

• Add an option to configure precision and scale for the unbounded numeric Postgres columns at the mirror creation.

[dominik-dezordo-vc]

Hey,

Because of this small change we currently need to run our own peerdb setup (including postgres/temporal). So this feature would significantly help our migration to clickhouse cloud