Updated the direct file upload/download to use the non-base64 approaches as well
Updated the attachment 'serverId' value to be a string instead of a UInt64 (future-proofing)
Updated the OnionRequest V4 response handling to avoid converting the "response body" part to a string and processing that, instead just slice the byte array (ie. stopped it from being broken from multiple conversions)
Removed the base64-based file upload/download endpoints (no use including them when they are inefficient and we don't want to use them)
Got the updated file upload working
Removed the legacy 'room' header
Consolidated a number of types between SOGS, FileServer and general requests
Updated the OnionRequestAPI to deal with a Data payload (rather than encoding it to a string and then back to data)
Added a couple more dependencies for unit testing injection
Updated the MessageSender to set the sender of the message to the appropriate blinded/unblinded key
Updated the OpenGroup Message to handle verification of both blinded and unblinded messages
Updated the MessageSender to use dependency injection for it's sendToOpenGroupDestination method
Updated the JSONDecoder to support getting dependencies (for signature verification)
Fixed tests broken by updating the signing logic
Cleaned up the OnionRequestAPI so we don't need the LegacyOnionRequestAPI
Added requests for the user endpoints
Added deprecated flags to the legacy endpoints and functions
Added some logic to start handling the new poll (batch) response
Started adding unit tests for the OpenGroupAPI functions
Added in the v4 onion requests logic
Added in the new pin/unpin APIs
Split up additional legacy methods to try and simplify the refactoring
Added a number of TODOs around usage of legacy request methods
Updated the MessageSendJob to support V4 messages (V2 messages will be upgraded to V4 if they get re-encoded)
Renamed the Message+Destination from 'openGroup' & 'openGroupV2' to 'legacyOpenGroup' and 'openGroup'
Started plugging in more of the V4 APIs
Renamed a number of the V2 APIs to start with 'legacy'