Add access to Jsoup class

[jwpjrdev]

In DefaultPowerschoolClient, you use the Jsoup object to scrape the site. However, I need to add a referrer. This, for me, is an issue, because, without it, I do not believe that I can connect.

Please provide an optional argument in DefaultPowerschoolClient#performLoginPost(String, String) of the type org.jsoup.Jsoup to override the default one.

Alternatively, I presume that I could implement PowerschoolClient, but if I do not have to, I'd rather not.

[jwpjrdev]

It looks like implementing PowerschoolClient is still quite a pain, and in the end, I had to switch to a different library in Node.