[CHANGELOG] Deprecation warnings for privacy, permissioning, PoW, fast sync

[macfarla]

PR description

for more info - https://www.lfdecentralizedtrust.org/blog/sunsetting-tessera-and-simplifying-hyperledger-besu

Thanks for sending a pull request! Have you done the following?

• Checked out our contribution guidelines?
• Considered documentation and added the doc-change-required label to this PR if updates are required.
• Considered the changelog and included an update if required.
• For database changes (e.g. KeyValueSegmentIdentifier) considered compatibility and performed forwards and backwards compatibility tests

Locally, you can run these tests to catch failures early:

• unit tests: ./gradlew build
• acceptance tests: ./gradlew acceptanceTest
• integration tests: ./gradlew integrationTest
• reference tests: ./gradlew ethereum:referenceTests:referenceTests

[matthew1001]

I think this is fine @macfarla, especially as it's currently just an announce. The one that I feel I could do with a bit more clarity on is the smart contract permissioning. The blog says "These features have existing and novel app-layer solutions" for tessera and smart contract permissioning, which I agree with for tessera, but I'm not as familiar with possible alternatives for smart contract permissioning.

[macfarla]

I think this is fine @macfarla, especially as it's currently just an announce. The one that I feel I could do with a bit more clarity on is the smart contract permissioning. The blog says "These features have existing and novel app-layer solutions" for tessera and smart contract permissioning, which I agree with for tessera, but I'm not as familiar with possible alternatives for smart contract permissioning.

agree there is some work to do to get permissioning plugin-able eg #7835

[diega]

Is it clear how plugin-able the PoW parts are?

[macfarla]

Is it clear how plugin-able the PoW parts are?

some work needs to be done still to make the consensus mechanism plugin-able - @diega is this something you'd be interested to contributing to?