Adding uds connection support to remove the need for deprecated socke…

[MahdiBM]

Sorry for the noises, didn't know renaming a branch will close its PR.

This is duplicate of https://github.com/vapor/postgres-nio/pull/301.

The Problem

Connecting through sockets has been deprecated in recent changes, which limits the ability to use uds for connections.

The Solution

This PR will add the ability to use uds using the new apis.

More

to not cause confusion: I rebased the commits into 1 since some changes from first commits were reversed.

[codecov-commenter]

Codecov Report

Merging #302 (cbc8ff5) into main (4b8ec14) will decrease coverage by 0.13%. The diff coverage is 20.00%.

@@            Coverage Diff             @@
##             main     #302      +/-   ##
==========================================
- Coverage   43.91%   43.78%   -0.14%     
==========================================
  Files         115      115              
  Lines        9680     9716      +36     
==========================================
+ Hits         4251     4254       +3     
- Misses       5429     5462      +33     

Flag	Coverage Δ
unittests	43.78% <20.00%> (-0.14%)	:arrow_down:

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...es/PostgresNIO/Connection/PostgresConnection.swift	16.49% <20.00%> (-0.65%)	:arrow_down:

[MahdiBM]

this last commit was stuck in Github client again due to the branch renaming i did. just adds the serverName back to the resolved connections.

[brucemontegani]

Can we get these changes reviewed please.

[fabianfett]

@MahdiBM Sorry, for taking so long to review this. I see the problem. However currently I'm not convinced that the approach taken, will serve us well into the future.

Sadly I haven't come up with a better one, yet. However I'm on it!

[fabianfett]

Superseeded by #335.