Support a catch all host which (almost) always matches the DNS request host

[bridgeythegeek]

This PR adds support for a [[zones]] entry for host with name __CATCH_ALL which will always match a host name when tested.

• The __CATCH_ALL answer is only provided if an exact match hasn't already been found in [[zones]] entries above the __CATCH_ALL entry in the toml file.
• [[zones]] entries below the __CATCH_ALL entry may also match as well as the __CATCH_ALL.

Resolves #21.

[codecov]

Codecov Report

Merging #22 (de88464) into main (a99dfe9) will decrease coverage by 2.53%.
The diff coverage is 57.14%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #22      +/-   ##
==========================================
- Coverage   97.54%   95.02%   -2.53%     
==========================================
  Files           4        5       +1     
  Lines         204      221      +17     
  Branches       37       42       +5     
==========================================
+ Hits          199      210      +11     
- Misses          3        7       +4     
- Partials        2        4       +2     

Files	Coverage Δ
dnserver/main.py	94.44% <57.14%> (-4.68%)	⬇️

... and 1 file with indirect coverage changes

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update a99dfe9...de88464. Read the comment docs.

[yooo1999]

Why that PR didn't merge?

[bridgeythegeek]

Hi @yooo1999, I deleted the PR because, after thinking about it, I thought it was a bad idea. This project is actually a mature DNS server. A "catch all" is almost certainly "a hack" used for testing and there are already projects that exist for this purpose, for example FakeDns and fakedns (personally, I use FakeDns).

[yooo1999]

@bridgeythegeek I still think that good idea for that project
But ...as you think