Sync main branch into main-nuxt

[yangwao]

It's time to continue on handovering to new branch stuff so we can be in sync and avoid ppl making PRs into old code.

• merge main into main-nuxt
• delete all stuff root connected with old SPA in main-nuxt
• put the context of folder /nuxt to the upper directory
• re-set deploy from root directory -- that's on @yangwao
• enjoy new PRs!

ref

#1060

[yangwao]

let's see

[yangwao]

Seems it's building!

[vikiival]

Migrating from SPA to SSG