Tendermint 0.35 to 0.34 production downgrade

Description: Tendermint 0.35 has been abandoned and is no longer supported. We need to first move to Tendermint 0.34 to be to upgrade to 0.37 which is the overall end target. This is necessary to increase our security and stability. This has already been researched as noted above. Production nodes have not been upgraded since August. This story is related to work done in #6 .

Story ROI
Business Objective: By moving to Tendermint 0.34 we will then be able to upgrade to 0.37 and increase security.

As an engineer, I want to migrate from Tendermint 0.35 to 0.34 to increase stability and security.

• Should get QA to prod-like state and fully test.
• Should document procedure for production and obtain team approval, schedule prod downgrade.
• Should run the downgrade to Tendermint 0.34 hybrid network in prod environment by snapshotting nodes one-by-one from the canary.
• Should thoroughly test Tendermint 0.34 downgrade on nodes (including stress and network stability tests).

Tasks:

Start with the prior research referenced in the issue and the related work in #6. Review the listed QA, production documentation, node snapshotting, downgrade, stress, and network-stability tasks. Done means Tendermint 0.34 is tested in a prod-like environment, the procedure is documented and approved, and the production downgrade is completed.