Add DAISIE_FAQ vignette

[Neves-P]

Adds DAISIE FAQ to vignettes from the document sent by @luislvalente.

I am not sure if we need to do anything else for the pkgdown website, but as far as I'm aware simply adding the vignette should be enough.

Please let me know if I missed anything!

Note regarding the dead links (e.g. at time of writing): https://cran.r-project.org/web/packages/DAISIE/index.html

The DAISIEprep, DAISIE, DDD, DAMOCLES, PBD packages on CRAN are returning "Object not found!" errors, as if the packages do not exist. They do show up as expected on https://cran.r-project.org/web/packages/available_packages_by_name.html. The packages might have been removed somehow and the available packages list is serving an old cached version, which is weird as normally removed packages would be archived with links to the archives if there is a problem. Otherwise, it could be something wrong with CRAN or some of it's mirrors. Contrast with tidyverse.

[joshwlambert]

Thanks @Neves-P! All looks good to me.

My guess is that the sites were down due to a CRAN server issue as it seems the packages were available for install throughout and all the sites are currently live.