Add draft JOSS manuscript

[egouldo]

• Set up draft manuscript skeleton and metadata, and package vignettes.
• Add references cited in manuscript to .bib
• Add references to bib
• Add text to summary section and statement of need section
• add lortie 2020 metaanalysis R package paper to bib
• Complete statement of need section
• Rerender .md manuscript
• Complete first draft of manuscript introduction
• close Incorporate feedback into draft manuscript #25 incorporate FF feedback
• Incorporate feedback into draft manuscript #25 rm italicisation on ManyEcoEvo project, except after first instance