Improve log streaming

[anbraten]

ATM logs are not really streamed live. There seems to be some buffering in between.

• remove Upload from rpc and only use logs to stream logs from agent to server
• remove usage of pipeline/multipart reader
• adjust log table to use proc_id, line, time, data
• save log stream directly line by line to DB after received by server
• stream log per child proc and not combined by parent proc
• stream logs of finished procs (like normal none-stream log call) and end stream after all data from db was send (make normal log call somehow obsolete at least for UI)

[6543]

Closed by #1802