We support 4 different config files:
~/.mitmproxy/common.conf: Options that are common to all tools
~/.mitmproxy/mitmproxy.conf: Options for mitmproxy
~/.mitmproxy/mitmdump.conf: Options for mitmdump
~/.mitmproxy/mitmweb.conf: Options for mitmweb
Options in the tool-specific config files over-ride options in common.conf. If
a non-common option is put in common.conf, an error will be raised if a
non-supporting tool is used.