large log files, avatars: allow configure, clear them (feature request)

Using 64-bit Keybase Debian package. Currently could not determine current issue in smartphone.

$ keybase version
Client:  4.1.0-20190612201656+952fee6c59
Service: 4.1.0-20190612201656+952fee6c59

$ ls -l ~/.cache/keybase/avatars/ | wc -l
2223

$ du -sh ~/.cache/keybase/avatars/
149M

When using ncdu (there are also precompiled binary for x86 and ARM available), it shows quite nicely used storage - also enormously large log files - can we configure log level (e.g. critical errors only, it means minimal or even turn it off) - would expect to configure it through GUI as well but certainly in CLI.

$ ncdu --color dark ~/.cache/keybase

~/.cache/keybase -----------------------------------------------------------------------
  148.2 MiB [##########] /avatars
  128.0 MiB [########  ]  keybase.service.log-20190618T140601+0300-20190618T221948+0300
  128.0 MiB [########  ]  keybase.service.log-20190618T221948+0300-20190619T105606+0300
   99.0 MiB [######    ]  keybase.service.log
   18.7 MiB [#         ] /attachments
   17.0 MiB [#         ]  keybase.kbfs.log
    4.8 MiB [          ]  Keybase.app.log.1
  696.0 KiB [          ]  Keybase.app.log
   64.0 KiB [          ] /uploadedpreviews
   64.0 KiB [          ] /uploadedfulls
    4.0 KiB [          ] /pendingpreviews
    4.0 KiB [          ]  keybase.ek.log
    4.0 KiB [          ]  keybase.app.serverConfig

Would propose:

• allow clear logs, attachments, avatars, uploaded/pending previews etc - separately and all together through GUI and also CLI (with appropriate parameters)
• allow configure in Settings and certainly via CLI with appropriate parameters:
  -- store avatars: on/off
  -- log level: critical, average, debug, turn off
  -- attachments: clear, set retention period: number | period (second, minute, hour, day, week, month, year)

Also allow to view through GUI the log files - at least allow to browse the containing folder - we can open log files also manually until Keybase is able to show log files itself and also search from log files, filter out some search strings, etc to benefit from the log files, especially in case when they are so big.

Also show below (at the bottom edge of the application window) at title bar small icons where I can see the size of:

• avatars folder
• attachments folder
• log files size summary
  ... and show also trash can icon per choice to erase saved files.

Currently there is a command at CLI:
keybase fs set-debug-level
... but help does not contain any information about which number applies to which level and how to turn off logging.

As in issue #17989 is issue only with avatars folder then I raise here also huge log files issue together with some improvements in Settings and CLI parameters to avoid such huge storage consumption issues by Keybase settings.

Start with the keybase fs set-debug-level CLI entry point and the Settings UI described in the issue. Define the scope with maintainers first; done would require agreed controls for log levels and cleanup or retention of logs, avatars, attachments, and preview files across CLI and GUI.