chore(nifi): Bump to 1.28.1, upgrade postgres jdbc driver

[NickLarsenNZ]

Part of stackabletech/docker-images#966.

• Update NiFi demos and custom image to 1.28.1
• Update the postgres jar and move it to a more appropriate image repository (it is not related to timescale).
• Update the docs to explain which dashboard is being described.
• Improve readability of the initialisation jobs.

Important

Despite the branch name, we are not bumping the demos to 2.2.0 as they rely on uploading templates.

Testing

• signal-processing
• nifi-kafka-druid-earthquake-data
• nifi-kafka-druid-water-level-data

[sbernauer]

Thanks for the bump! Can you please make sure the demos are still working? I recall having problems bumping to 2.0.0 in the last release cycle

[NickLarsenNZ]

Thanks for the bump! Can you please make sure the demos are still working? I recall having problems bumping to 2.0.0 in the last release cycle

We have a separate task to test demos, but I can do a quick test now before merging.

I believe it is still the case that upgrading from 1.x.x to 2.x.x is breaking (as indicated by the major version), but there don't appear to breaking changes from 2.0.x to 2.2.x judging by the release notes: https://cwiki.apache.org/confluence/display/NIFI/Release+Notes#ReleaseNotes-Version2.2.0)

[NickLarsenNZ]

It looks like there are some big changes.

At least, the signal-processing demo doesn't work as it depends on nipy which doesn't fully support NiFi 2. See: Chaffelson/nipyapi#380.

So, We could just make the demo use 1.28.1. What do you think @sbernauer?

[sbernauer]

Yes, seems like I recalled correctly :/

I would leave the decision to you.
My only 2 cents is that we need to do the bump eventually and I we should not accumulate to much technical debt ;)

[NickLarsenNZ]

Yes, seems like I recalled correctly :/

I would leave the decision to you. My only 2 cents is that we need to do the bump eventually and I we should not accumulate to much technical debt ;)

It has been decided that 2.x will remain experimental until we can support flow/template uploads via NiFi Registry.

I will therefore bump these demos to NiFi 1.28.1, and if we're lucky, convert the Flow to JSON within the repo.

[sbernauer]

LGTM if demos still work.
Very nice addition with the init containers, thank you!