v0.29.0: Freezing fees, better signature aggregation and better network reliability

Major improvements since v0.28.0:

Introduce Freezing fee: #2597

Freezing TXs now have to include SlashAmountPenatly amount of fee
for each Freeze output they have. This amount will be refunded to them
if they are not slashed for the duration of their validation cycle.

Add missing signatures if possible on fetched blocks and headers: #2727

The missing signatures that are known are added and gossiped to peers. This will help ensure that we have all the available signatures stored in the block header as soon as possible.

Add TransactionResult struct for result of posting transaction: #2723

A struct is now returned with a status of Accepted, 'Rejected' or Duplicated and a reason if rejected.

Fix utility retry logic to also wait when exception occurs: #2713

This prevents many successive failures without delay between retries.

Only use unidentified connections for address discovery: #2710

This helps to prevent edge cases that are difficult to handle.

Deserialize RDATA for supported types: #2711

Deserialize Resource Records fetched through AXFR query (Domain requires special deserializer context).

Registry: Only answer with records matching query type: #2715

DNS: Merge two definitions of RDATA: #2719

Manager: Try to connect to last known Validators: #2722

This will enable a validator to catchup after a restart even when it is not enrolled.

Validator: Push BlockHeader on new signatures received: #2725

This will ensure the listeners are kept up to date with latest header updates.