[FEATURE] Support pytest config file options

[dragonpaw]

Is your feature request related to a problem? Please describe.
Support options in pytest config file

Describe the solution you'd like

[pytest]
block_network = True
ignore_localhost = True
allowed_hosts = [ "::1" ] # Ipv6 localhost isn't considered localhost.

Describe alternatives you've considered
I know I can use addopts, but my addopts line is getting very, very long... ;)

Additional context
Great plugin, love it!