Save profile data on the server side

[markccchiang]

Description

• What is implemented or fixed? Mention the linked issue(s), if any.
  Implement [data interfacing] save profile data at the server-side (backend) #1342.

• How does this PR solve the issue? Give a brief summary.
  Create a class DataExporter to handle the export of profile data on the server side. The frontend sends CARTA::EventType::EXPORT_DATA with CARTA::ExportData message to the backend. The backend replies CARTA::EventType::EXPORT_DATA_ACK with CARTA::ExportDataAck message to indicate whether the data export is successful or not. Note that the profile data file can not be saved on the directory that does not exist.

• Are there any companion PRs (frontend, protobuf)?
  It requires changes in the frontend and protobuf (temporary branch: mark/save_profile_data).

• Is there anything else that testers should know (e.g. exactly how to reproduce the issue)?

Checklist

• changelog updated / no changelog update needed
• e2e test passing / corresponding fix added / new e2e test created
• ICD test passing / corresponding fix added / new ICD test created
• protobuf updated to the latest dev commit / no protobuf update needed
• protobuf version bumped / protobuf version not bumped
• added reviewers and assignee
• added ZenHub estimate, milestone, and release

[github-actions]

Package	Line Rate	Health
src.Cache	72%	➖
src.DataStream	44%	➖
src.FileList	67%	➖
src.Frame	36%	❌
src.HttpServer	42%	➖
src.ImageData	28%	❌
src.ImageFitter	83%	✔
src.ImageGenerators	43%	➖
src.ImageStats	75%	✔
src.Logger	37%	❌
src.Main	52%	➖
src.Region	69%	➖
src.Session	4%	❌
src.Table	52%	➖
src.ThreadingManager	67%	➖
src.Timer	85%	✔
src.Util	41%	➖
Summary	46% (8642 / 18841)	➖