* extract shared db conn + data repository
* extract repository interface
* protect against nested transactions
* fix mysql and db conn creation
* fix context management
* remove query warpper
* remove withContext and withLock wrapper
* remove context from function call
* remove in memory mode
* fix nested transaction handling
* use db directly
* remove leftover test
* remove pool close on error during conn creation
TestGetNetworkMapData serialises the whole network map and compares it with
network_map_data_golden.json. DebugBundleUploadURL joined
nmdata.AccountSettingsInfo, so it now appears in that serialisation and the
golden file no longer matched.
Regenerated with NMAP_UPDATE_GOLDEN_DATA rather than hand-edited; the diff is
the one expected line.