Allow user to modify upload/download limits

[tuxfoo]

Allow the user to set the download/upload connection limits via the config file.

Some users might want to increase these if they have fast connections(eg; gigabit fibre)

The limit only needs to be applied when the script/cron job is run.

• [ ] "max_connections_per_download"

• [ ] "concurrent_reflector_uploads"

The lbrynet settings are listed here https://lbry.tech/resources/daemon-settings