Fixes and improvements to prepare for v0.8.0 release of FunLess

[mattrent]

This PR adds various missing features and fixes some long and short-lived bugs in the CLI, to align with the current version of the platform and improve the usability and functionality of the command line.

The tasks described below will be updated as they are completed, along with additional notes.

Specifically, this PR:

• Removes the hardcoded host from the client config, and reads it from an existing config file (closes Use a config to hold apihost #13)
• Adds the possibility for the user to specify the host in every command, overwriting the existing config (closes --host flag to specify custom host #14)
  • The custom host has been added to fn, mod and user subcommands, where the API is actually used
  • The custom host is set in the parent commands, and then passed via context value to the various handlers
• Adds authentication headers for all API calls (fn, mod and user), allowing communication with the new version of FunLess
• Adds Config Management commands (fl config set <property> <value>/fl config get <property>)
• Fixes the linter bug in CI (closes Lint CI not working #124)
  • This requires further testing. The crashes in CI are due to timeouts, so increasing the tolerance should work (it is now working on my repo). The issue mentions an OS crash that I wasn't able to reproduce in my system (Ubuntu 22.04.1 LTS, 5.19.0-35-generic).
• Adds the SECRET_KEY_BASE variable in the config file
• Injects the SECRET_KEY_BASE during deployment, both on Docker and k8s, allowing the proper initialization
• Extract guest/admin tokens from containers after deployment in Docker and k8s and insert them in the config file
  • For simplicity, tokens are just logged after deployment; users can set them in the config file separately using the cfg command
• Fixes docker-compose bug with custom images (closes Incorrect behaviour in Docker deployment with custom images #121)