This commit updates geth to 1.8.17 and adds a possibility to enable metrics during compilation time.
The cascade of issues forced us to upgrade geth to 1.8.17 in order to allow enabling metrics during compilation time. 1.8.17 introduced `NodeID` refactoring and `enode` package which affected our peers pool and integration with Discovery V5.
- Replace deprecated common.Hex with hexutil.Encode.
- Remove upstreamed 0010-geth-17-fix-npe-in-filter-system.patch.
- Remove upstreamed 0020-discv5-metrics.patch.
- Remove upstreamed 0026-ethdb-error-deadlock.patch.
- Update goleveldb to same version used by geth 1.8.11.
- Update PublicTransactionPoolAPI.GasPrice return type to match type in internal geth interface.
