Check cookies function

[jnxxx]

An attempt to implement the suggested check of the cookies string.
It checks if there are other cookies than the five I saw using the incognito mode. It seems when doing it from a normal tab where cache was not properly cleared there are more, or at least could very well be.
It is merely a warning. Users may choose to continue anyway.

You may use it, or choose not to.
Just my two cents.

[iMicknl]

Thanks! I won't merge it directly, but will make sure this is part of the V2 release. Will need to do some testing myself first.

Would you be willing to also improve the instructions in the README (or in the Config Flow).

[jnxxx]

I have now tried to update the instructions on how to retrieve issue_token and cookies.
It is mainly incorporation of #272, and a bit of formatting and checking menu names etc.

Furthermore I added a description to the account selection step.
I am not really sure myself, but seems to be production and test. So, basically saying to use the default one.
The link in the second step is fine (points to beta branch though).

I do not have a Mac available, so I cannot check the findings reported there.
The menu layout could be different and searching in dev. tools, but the core browser functionality should hopefully be the same.

Regarding issueToken and oauth2/iframe (last entry) finding the same request: I do see this, but only if there was a session already. If clearing cookies or using Incognito it is two different requests. Therefore I kept this.
The issueToken request gets the same cookies as input/request, but updates one of them which can be found under response. Rather than user having to merge request and response cookies, oauth2/iframe (last entry) finds the subsequent request where most recent cookies can be found under request cookies.
Based on my own experience, I would just recommend using Incognito now there is a description on how to work around the third-party cookie issue.