Harvesting: Join "Key links" and "Persistent delegated message" steps

[cryptoBeliever]

At this moment harvesting in mobile and desktop wallets is working in the following way:

1. Create Account Links (Remote, VRF, Node).
2. Send a persistent delegated message to Node.

Those two steps can be joined in one aggregate transaction. This will simplify a lot of harvesting views (for single and multisig accounts). Important is only to put a persistent delegated message in aggregate after key links transaction.

Example here: https://symbol.fyi/transactions/43748B7F9868E624A72F8D81A394C2CBCF1A4021B5DF255501B1B9BAD2D494D6

@yilmazbahadir the question if we need graphics?

[segfaultxavi]

Please update the docs if this ever gets implemented! https://docs.symbolplatform.com/guides/harvesting/activating-delegated-harvesting-wallet.html