Handle and pipe bridge rate limit error related to free tier to goobox-community-gui

[MeijeSibbel]

If a user uploads beyond the free tier (25GB) limit, which includes the hourly (3GB/h) and daily (10GB/day) limits the bridge will send rate limit errors, these should be identified and handled. With this endpoint we can then inform users that use the community app that they can't upload anymore due to this limit. Currently the free tier structure is a mess as (1) erasure encoding extra size is not taken into account and (2) the free tier simply doesn't work for many people.

storj-archived/bridge#505
storj-archived/storj.io#90

[MeijeSibbel]

This info should be piped to the GUI which then sends a notification to the user.