Store curation information and default nomenclatural code in cookies

[gaurav]

While writing the tutorial, I realized that users currently need to re-enter their name, e-mail address and ORCID every time they create a new Phyx file. This PR changes that so that those four pieces of information -- as well as the default nomenclatural code -- are stored in the users' browser in cookies for 30 days.

Should be merged after PR #259.

[hlapp]

Looks good and is indeed welcome. Now that we're storing cookies in a client's web browser I also think we should at the very least say somewhere that we're doing this. But this can be a separate issue.

[gaurav]

I've added a checkbox to the "Phyloreference collection" box that looks like this:

As described, the checkbox will either turn on cookies (by creating a COOKIE_ALLOWED cookie on the browser, which allows the getting and setting of cookies to proceed) or -- if unchecked -- delete all Klados cookies, including the COOKIE_ALLOWED cookie. Note that the curation information is in the old format; I'm working on an improved curation information format in phyloref/phyx.js#119.

Here's the text if you would like to suggest improvements:

Click this checkbox if you would like Klados to save your curator information and default nomenclatural code as a browser cookie for the next month, or uncheck it to delete all Klados cookies from your browsers.

[hlapp]

Looks good, except I suggested some changes to the label for the checkbox. BTW your phrasing of for the next month is ambiguous (open to various interpretations): for the next 30 days? until the end of the next month? until the end of this month? I chose one interpretation, but you should substitute the correct and unambiguous one.