Remove puppeth & account management (#1610)

accounts/abi/bind/auth.go

accounts/accounts.go

accounts/accounts_test.go

accounts/errors.go

accounts/external/backend.go

accounts/hd.go

accounts/hd_test.go

accounts/keystore/account_cache.go

accounts/keystore/account_cache_test.go

accounts/keystore/file_cache.go

accounts/keystore/key.go

accounts/keystore/keystore.go

accounts/keystore/keystore_test.go

accounts/keystore/passphrase.go

accounts/keystore/passphrase_test.go

accounts/keystore/plain.go

accounts/keystore/plain_test.go

accounts/keystore/presale.go

accounts/keystore/testdata/dupes/1

accounts/keystore/testdata/dupes/2