Figure out how to format tags page and what the terms.html partial does

[lucharo]

I like tags like these: https://prose.yihui.org/tags/ and ideally I'd have them by section (pages, notes), see:

• https://discourse.gohugo.io/t/taxonomies-per-section/18423/4
• https://gohugo.io/content-management/taxonomies/
• https://discourse.gohugo.io/t/tags-within-sections/36276
• https://discourse.gohugo.io/t/how-can-i-list-tags-by-section/34407/3
• https://gohugo.io/templates/lists/
• https://discourse.gohugo.io/t/list-all-pages-in-sub-folder/28063/4