chore(lint): add nilnil, nilerr and exportloopref linters

[qdm12]

Changes

• Add nilnil, nilerrandexportloopref` linters
• Fix lint errors whenever possible or add //nolint comments when not applicable

Tests

golangci-lint run

And CI to pass

Issues

• Improve linting to detect potential memory problems #1974

Primary Reviewer

[codecov]

Codecov Report

Merging #2072 (f2a7d9e) into development (6f9f730) will decrease coverage by 0.01%.
The diff coverage is 52.77%.

@@               Coverage Diff               @@
##           development    #2072      +/-   ##
===============================================
- Coverage        61.25%   61.23%   -0.02%     
===============================================
  Files              203      203              
  Lines            27344    27341       -3     
===============================================
- Hits             16749    16743       -6     
- Misses            8717     8720       +3     
  Partials          1878     1878              

Flag	Coverage Δ
unit-tests	61.23% <52.77%> (-0.02%)	⬇️

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

Impacted Files	Coverage Δ
dot/state/grandpa.go	40.50% <0.00%> (+0.40%)	⬆️
lib/genesis/test_utils.go	0.00% <0.00%> (ø)
lib/grandpa/message_handler.go	64.42% <0.00%> (ø)
lib/runtime/life/resolver.go	61.70% <0.00%> (ø)
lib/runtime/wasmer/imports.go	48.66% <0.00%> (-0.26%)	⬇️
dot/sync/chain_sync.go	55.08% <33.33%> (-0.15%)	⬇️
lib/babe/epoch.go	60.16% <71.42%> (-0.33%)	⬇️
dot/rpc/modules/state.go	95.41% <100.00%> (+0.02%)	⬆️
dot/sync/bootstrap_syncer.go	74.07% <100.00%> (ø)
dot/sync/tip_syncer.go	82.75% <100.00%> (ø)
... and 4 more

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[kishansagathiya]

🎉