breaking(charm): Replace NGINX ingress with Traefik

[pedro-avalos]

Description

• This PR replaces NGINX with Traefik as the ingress for the server charm.
• NGINX is deprecated and most of our projects are turning to traefik as the ingress of choice.

Related Issue(s)

Resolves HWAPI-61

Testing

• Integration tests

• Manual testing steps:

  1. Set up Juju environment
  2. Pack charm
  3. uvx tox run -e integration

Checklist

• I have followed the contribution guidelines.
• I have signed the Canonical CLA.
• I have added necessary tests.
• I have added or updated any relevant documentation (if needed).
• I have tested the changes.

Additional Notes

This PR adds traefik-k8s and lego as components to be deployed in the product Terraform modules. These are to ensure that we can pull in a TLS certificate (NGINX pulled it from a K8s secret, but we are moving towards using LEGO credentials).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.30%. Comparing base (77d1117) to head (81c8356).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #491      +/-   ##
==========================================
+ Coverage   89.20%   89.30%   +0.09%     
==========================================
  Files          28       28              
  Lines        1390     1403      +13     
  Branches        1        4       +3     
==========================================
+ Hits         1240     1253      +13     
  Misses        150      150              

Flag	Coverage Δ		*Carryforward flag
charm	100.00% <ø> (ø)		Carriedforward from 7c3f8be
client	80.24% <ø> (ø)		Carriedforward from 7c3f8be
server	97.01% <ø> (-0.03%)	⬇️	Carriedforward from 7c3f8be

*This pull request uses carry forward flags. Click here to find out more.

Components	Coverage Δ
Server	96.85% <ø> (ø)
Charm	100.00% <100.00%> (ø)
Client	80.24% <ø> (ø)

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