Adds a new `Info` method to the Kademlia endpoint that returns the following local node info:
* ID
* Type
* Metadata (email and wallet)
* Restrictions (free storage and bandwidth)
The new endpoint is exposed as `inspector kad node-info` command too.
* Pulls statdb stats into overlay cache whenever cache.Put() is called
* Updates overlay.FindStorageNodes()/overlayClient.Choose() to filter based on node stats
* Updates overlay.FindStorageNodes()/overlayClient.Choose() to exclude duplicate IP addresses
* preparing for use of `customtype` gogo extension with `NodeID` type
* review changes
* preparing for use of `customtype` gogo extension with `NodeID` type
* review changes
* wip
* tests passing
* wip fixing tests
* more wip test fixing
* remove NodeIDList from proto files
* linter fixes
* linter fixes
* linter/review fixes
* more freaking linter fixes
* omg just kill me - linterrrrrrrr
* travis linter, i will muder you and your family in your sleep
* goimports everything - burn in hell travis
* goimports update
* go mod tidy
