add j2lint & cleanup jinja templates

[ryanmerolle]

Waiting on feedback for opsmill/infrahub#8182 to further reduce template noise gven the usage of hyphens to address whitespace issues.

[petercrocker]

Hey @ryanmerolle this is failing an integration test:

Primary failure: No filter named 'ipaddress_interface'

jinja2.exceptions.TemplateAssertionError: No filter named 'ipaddress_interface'.
The PR replaced all instances of .split('/')[0] (vanilla Jinja2 string manipulation to strip CIDR prefix from IPs like 10.0.0.1/32 → 10.0.0.1) with | ipaddress_interface(attr='ip'). This filter comes from the netutils library but is not registered in Infrahub's Jinja2 environment, so the templates fail at render time.

This cascades into the final test failure:

FAILED tests/integration/test_workflow.py::TestDCWorkflow::test_13_merge_proposed_change
The proposed change couldn't merge because the transforms (which render these templates) were all failing.

[petercrocker]

Closing in favor of #56 which rebases this work onto current main. The integration test failure was caused by stale dependency versions (infrahub-testcontainers 1.6.1 vs 1.7.7). Thank you @ryanmerolle for the original contribution!