Project Board clean up

[jwokaty]

@sonali8434 We've really appreciated your help in moving Sweave2Rmd further along through conversions, outreach, and improved documentation to mention a few of your contributions. Thanks for cleaning up the board during last week as an Outreachy intern with Bioconductor. Let's focus on the following

• Add GitHub repository URLs to unassigned vignettes
• If a maintainer is interested, set the status to 'Todo'
• Set difficulty for vignettes
• Add URL to issue for vignettes with a status of Contacted who were contacted by a GitHub issue*

I'll also note here as we discussed that if you have marked a vignette as 'Contacted' that the maintainer has been contacted once and the last date of contact is the date last modified.

*For vignettes with a status of Contacted, could you include the URL to the issue if you used an issue for communication? This way we will know how to continue dialogue with the maintainer. For those that do not have a URL, we will assume they were contacted by email.