Allow blank DB host value, reuse backend code

[AlanCoding]

SUMMARY

This avoids us create a "connection string" which was already believed to be brittle and undesirable.

Here are some research links of various value:

https://github.com/django/django/blob/main/django/db/backends/base/base.py#L30

https://github.com/django/django/blob/main/django/db/backends/postgresql/base.py

This create the same thing as django.db.connection, but using that object specifically comes with a lot of baggage. It's much cleaner to just create it, as what we need is set up in its __init__. This avoids touching the already active connection, which is being used for other stuff. The deepcopy we already had still seems like a good idea.

The idea is that "HOST" in the DATABASES setting may be an empty string. Instead of handling this specifically, I'm trying to do it the "right" way finally here. Presumably this works for password-less auth which we were already trying to allow.

Essentially, we have to "translate" the Django database settings into the psycopg parameters, and instead of doing it manually we will use the logic already written in Django.

ISSUE TYPE

• Bug, Docs Fix or other nominal change

COMPONENT NAME

• API

[AlanCoding]

Still trying to get more test results before merging, which will have to wait until the dependencies are fixed.

[AlanCoding]

Link related associated fixes:

• Make db password optional for wsrelay #15046
• LISTENER_DATABASES clobbers DATABASES OPTIONS in wsrelay #15306

Reviewing these, the only valid concern that comes up is that we should also do this in awx/main/wsrelay.py. That might be important enough to block merging this until resolved. This likely dictates a utility method to convert the "settings_dict" to psycopg params. This could help with testing. We should add tests...

[AlanCoding]

I was hesitant to include this in the current PR, so I made a new branch:

https://github.com/ansible/awx/compare/devel...AlanCoding:wsrelay_params?expand=1

Will test that separately.

[AlanCoding]

^ that passes tests. I checked the wsrelay logs and didn't see any problems.

I have to expand the scope of this, but it's just not worth it without this broader change, so I'm pushing it. Really hate to do this, but will have to ask for a re-review with that.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[AlanCoding]

This was mostly moved to DAB. Hopefully we did it correctly there.

[codecov]

Codecov Report

❌ Patch coverage is 75.86207% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 74.35%. Comparing base (6228fe9) to head (f75b92d).
⚠️ Report is 463 commits behind head on devel.

❌ Your patch status has failed because the patch coverage (75.86%) is below the target coverage (100.00%). You can increase the patch coverage or adjust the target coverage.
❌ Your project status has failed because the head coverage (74.35%) is below the target coverage (100.00%). You can increase the head coverage or adjust the target coverage.

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