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.
* mailserver sends envelopes in descending order
* add limit value in mailserver request payload
* mailserver sends messages up to the limit specified in the request
* update Archive method to return key and error
* processRequest returns the next page cursor
* add cursor to mailserver request
* add limit and cursor to request payload
* fix request limit encoding
* wait for request completed event in TrackerSuite/TestRequestCompleted
* add cursor to mailserver response
* fix cursor position in payload
* add e2e test for mail server pagination
* validate mail server response size
* remove old limitReached var
* fix lint warnings
* add whisper patch
* fix tests after rebase
* check all return values to avoid lint warnings
* check that all messages have been retrieved after 2 paginated requests
* fix lint warnings
* rename geth patch
* merge mailserver patches into one
* add last envelope hash to mailserver response and EventEnvelopeAvailable event
* update whisper patch
* add docs to MailServerResponse
* update whisper patch
* fix tests and lint warnings
* send mailserver response data on EventMailServerRequestCompleted signal
* update tracker tests
* optimise pagination test waiting for mailserver to archive only before requesting
* rollback mailserver interface changes
* refactoring and docs changes
* fix payload size check to determine if a limit is specified
* add more docs to the processRequest method
* add constants for request payload field lengths
* add const noLimits to specify that limit=0 means no limits
* refactor TestRequestMessageFromMailboxAsync to use s.requestHistoricMessages helper
* send p2pRequestResponseCode from mailserver
* send p2p message response to after sending all historic messages
* mailserver sends `whisper.NewSentMessage` as response
* add mailserver Client and p2pRequestAckCode watchers
* send event with envelopeFeed when p2pRequestAckCode is received
* test request completed event in tracker
* rename mailserver response events and code to RequestCompleteCode
* wait for mailserver response in e2e test
* use SendHistoricMessageResponse method name for mailserver response
* fix lint warnings
* add mailserver request expiration
* send mailserver response without envelope
* add `ttl` to Request struct in shhext_requestMessages
* test that tracker calls handler.MailServerRequestExpired
* add geth patch
* rename TTL to Timeout
* split tracker.handleEvent in multiple methods
* Rebase on 1.8.5
* Remove outdated patches and apply all others
* Use shh_post that returns hash
* Use bloom filter for request to mailserver
* Remove tests for sending messages without subbing first
* Fix deadlock in ethdb
* Expect null if receipt is not yet created
* Subscribe to messages before sending them in whisper test
* Implement shh api extension that allows to confirm that message is sent
* Add a patch
* Fix linter
* Add readme
* Add tests for tracker
* Address review
