Cleanup for latest go-ethereum merge

[ghost]

@strangepowers @priom @ChainSafe @noot

Needed for go-ethereum PR 😄

Changelog

• Gofmt for go linter test
• Changed default goreli genesis block to match with Parity ( Still WIP, need fix on Aura engine )
• Removed build-related files
  + Updated files based on go-ethereum 72c820c

TO-DO list

• Fix Aura engine port for go since it is not working with parity-geth chain connection yet
• Fix Aura engine port to work with several geth unittest ( Please check them with go run build/ci.go test )
  + Rebase commits with latest go-ethereum branch and squash them into 1 maybe?? ( Current files are updated with go-ethereum 72c820c commit you can rebase on top of it 😄 )

Here is the example pr opened for go-ethereum ethereum#17668

PS) Please check these compile errors with go linter

consensus/aura/aura.go:100:2:warning: unused variable or constant errInvalidCheckpointSigners (varcheck)
consensus/aura/aura.go:47:2:warning: unused variable or constant wiggleTime (varcheck)
consensus/aura/aura.go:71:2:warning: unused variable or constant errInvalidCheckpointBeneficiary (varcheck)
consensus/aura/aura.go:75:2:warning: unused variable or constant errInvalidVote (varcheck)
consensus/aura/aura.go:79:2:warning: unused variable or constant errInvalidCheckpointVote (varcheck)
consensus/aura/aura.go:83:2:warning: unused variable or constant errMissingVanity (varcheck)
consensus/aura/aura.go:91:2:warning: unused variable or constant errExtraSigners (varcheck)

obsolete

[5chdn]

please split gofmt and upstream changes in 2 PRs

and maintain upstream commit history please

[ghost]

@5chdn Done sorry for confusion 😄