V7.3.0-rc3

Changelog

• Updated Trust Graph with pyqtgraph replacing matplotlib
• Fix false broken DB warning in logger
• Fixed metadata store DB name
• Fixed metainfo NoneType issue in TorrentDef
• Fixed GUI crash during shutdown
• Disabled finished notification for channel download
• Fixed bootstrap log for seeder
• Fixed crash when health response is None
• Polished torrent creation dialog
• Added gossip for only complete channels
• Removed requirement for six 1.12
• Updated IPv8 pointer