Refactor 2fa

[stelle11]

I did a complete refactoring of the 2fa authentication because of multiple issues I had related to #96. I was only using yahoo for my tests but I did multiple different tests that also covered the issue desribed in #96. These changes fixes #96 in my opinion.

The issues I had with the existing code was:

• No deletion of the authentication mails received every 6 minutes when pyaarlo couldn't log in
• If multiple authentication mails was in the inbox it would always only read the first received mail (not the newest)
• The 2fa authentication could not read the code in the mail correctly - #96

Quick description of the refactoring changes:

• Get mail ids for all mails in the inbox
• Only take the last 10 mail ids
• If any of them (starting from the newest) is from Arlo then try to read the code and return it
• Otherwise wait for a new mail to arrive then check latest 10 mails again

I did the following tests after having everything fully implemented:

• Waiting for the authentication mail with no other authentication mails in the inbox
• Waiting for the authentication mail with more than one other authentication mail in the inbox
• Read the latest authentication mail with no other authentication mails in the inbox
• Read the latest authentication mail with more than one other authentication mail in the inbox

I did make some changes to the code like instead of using imaplib's search function to find all mails from do_not_reply@arlo.com, I changed to get all mail ids and check the sender of the last 10 mails. The reason being that the search function did not return all mails from do_not_reply@arlo.com. The search function does not work if there's more than 10K mail ids - at least not with yahoo.

[twrecked]

I'll give this a try here with gmail and apple.

One thing, it's removing the SSL options change and read-only change from this commit: https://github.com/twrecked/pyaarlo/pull/104

[Jopand]

Tried out this change. At first I thought this PR fixed the #96 issue, but it turned out I was fooled by an existing token. When that ran out, I couldn't do a new 2fa login. So I reverted to the fix I mention in #96.