ci: remove unused goreleaser files, ignore chain/ tags

[thehowl]

I don't know how to test this, but I think this may fix it. @ajnavarro do you have a separate repo / access to the pro token and can see if this configuration works?

I removed the other config files as they weren't used, and the nightly: section as I don't think it's parsed, anyway: it doesn't exist in the goreleaser schema.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 63.38%. Comparing base (1a57e81) to head (9e2507a).
Report is 7 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3004      +/-   ##
==========================================
+ Coverage   63.37%   63.38%   +0.01%     
==========================================
  Files         561      565       +4     
  Lines       79199    79441     +242     
==========================================
+ Hits        50189    50352     +163     
- Misses      25625    25697      +72     
- Partials     3385     3392       +7     

Flag	Coverage Δ
contribs/gnodev	59.94% <ø> (-0.63%)	⬇️
contribs/gnofaucet	14.82% <ø> (-0.95%)	⬇️
gno.land	67.37% <ø> (-0.01%)	⬇️
gnovm	67.86% <ø> (-0.08%)	⬇️
misc/genstd	79.72% <ø> (ø)
tm2	62.42% <ø> (+0.16%)	⬆️

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[sw360cab]

Tried locally.
LGTM