Added support for mail.tm

[bolshoytoster]

• I now use a modified version of the random_email function for generating emails for mail.tm

Changes to random_email:

• I removed the lambda expressions with dots in them - mail.tm strips dots from it's emails.

• Doesn't pick domain from a preprogrammed list anymore - it gets the domain from mail.tm via it's api

• Added a command line option, --mailtm. Using this will use mail.tm by default
  If you don't use that option, it will automatically fallback to it if guerrilla
  doesn't respond within 180 seconds (let me know if it's a bit much) and vice versa

mail.tm pipeline

• In random_email, we get the domain to use from the /domains endpoint
• Create the account with the /accounts endpoint
• Get the token used to access the account from the /token endpoint
  ...
  sign up
  ...
• Checks inbox with the /messages?page=1 endpoint every 1.5 seconds until the email arrives
• Fetches the email from /messages/{id}