feat: allow form filling based on processing of get parameters for submit_new_license

[alandtse]

I'll be adding a submit new licenses option in spdx-license-diff. This will try to populate some of the fields on the submit_new_license page. While there is a character limit for URIs, it'd be helpful for me to pass the request in a get request to prepopulate the fields that will already be available. I could also do a post request to prepopulate if that helps.

My understanding is that django can enable this fairly easily. Looking at the current form, I'd only prepopulate:

• sourceUrl
• text
• comments

[alandtse]

Solved this via javascript.