Create initial project structure

[ikopylov]

Linked issue: qoollo/bob#245

Decide whether the frontend will be done as SPA with some popular framework (Angular, React, ect.) or with a server-side templates.
If the first, then separate folders should be created for frontend and backend in the root of the repository. If the second, then the folder with the name src should be created for the source code.

After that the initial project structure should be created (both for backend and frontend if they were separated).

Also some shared template for web-pages should be added (menu on the left, name on the top, content in the center; something like minio console)