Solution
Since BigchainDB and Tendermint are so tightly coupled we need to introduce a process supervisor to make them act like a single microservice, so that if BigchainDB crashes, Tendermint does as well and both are restarted and Tendermint requests a connection towards the proxy app.
In Kubernetes, they can be exposed as part of a one POD.
For BigchainDB as a system service/process, we need to introduce a process supervisor such as systemd.
This PR only solves the former.
Changes
Upgrade deployment from Tendermint v0.12.0 to v0.19.0
Update some documentation
Fix nginx-http entrypoint issues.
Update generate-configs.sh script to handle config generation without https-certificates.
Update Dockerfile to process dependency links introduced by abci
Integrate BigchainDB and Tendermint as a single microservice.
This required making BigchainDB to be exposed as a statefulset.
Introduce new liveness probe checks.
Issues Resolved
Partially fixes#2232
* Combining configs
* Combining the persistent volume claims into a single file.
* Combining the storage classes into a single file.
* Updating documentation
* Multiple changes
* Support for ConfigMap
* Custom MongoDB container for BigchainDB
* Update documentation to run a single node on k8s
* Additional documentation
* Documentation to add a node to an existing BigchainDB cluster
* Commit on rolling upgrades
* Fixing minor documentation mistakes
* Documentation updates as per @ttmc's comments
* Block formatting error
* Change in ConfigMap yaml config
