[apps] Docker only show current containers

[Npeca75]

RRDs associated with APPs are created when new APP is discovered, but newer deleted until RRD purge period. This is normally few months/year
one of problematic APPs is Docker
Problem is that LibreNMS will stack these inactive RRDs on graph, so after few "lets try some containers" it is getting messy. Dozen of inactive RRDs are shown in cumulative graph

This PR add filter ability to filter out unused RRDs matching against active APPs in ApplicationMetrics table

DO NOT DELETE THE UNDERLYING TEXT

Please note

Please read this information carefully. You can run ./lnms dev:check to check your code before submitting.

• Have you followed our code guidelines?
• If my Pull Request does some changes/fixes/enhancements in the WebUI, I have inserted a screenshot of it.
  (https://docs.librenms.org/Developing/os/Test-Units/).

Testers

If you would like to test this pull request then please run: ./scripts/github-apply <pr_id>, i.e ./scripts/github-apply 5926
After you are done testing, you can remove the changes with ./scripts/github-remove. If there are schema changes, you can ask on discord how to revert.

[Npeca75]

Before

[Npeca75]

... after

[murrant]

NACK from me.

There is a new data field on the applications table. Just store the list of current application items there and use that to generate the graphs directly.

[Npeca75]

hi @murrant

There is a new data field on the applications table.

ok, first time dealing with this field
done as in ZFS
hope it is OK now

[murrant]

Much better! Thanks @Npeca75