refactor: use TOML for configuration file (#1228)

* refactor: remove jsconfig.json

* chore: remove devcontainer config

* refactor: migrate Hugo configuration from `hugo.yaml` to dedicated `module.toml` and `params.toml` files, and update minimum Hugo version.

* refactor: migrate demo site configuration from `hugo.yaml` to `config/_default/*.toml`

* feat: enable local sidebar avatar for demo site and relocate its image to demo assets.

* feat: migrate demo site to Hugo Modules for theme management.

* fix: wrong config folder name

theme.toml

@@ -1,12 +1,12 @@
 # theme.toml template for a Hugo theme
 # See https://github.com/gohugoio/hugoThemes#themetoml for an example
 
-name = "Stack"
-license = "GPL-3.0-only"
+name        = "Stack"
+license     = "GPL-3.0-only"
 licenselink = "https://github.com/CaiJimmy/hugo-theme-stack/blob/master/LICENSE"
 description = "Card-style Hugo theme designed for bloggers"
-homepage = "https://github.com/CaiJimmy/hugo-theme-stack"
-demosite = "https://demo.stack.jimmycai.com"
+homepage    = "https://github.com/CaiJimmy/hugo-theme-stack"
+demosite    = "https://demo.stack.jimmycai.com"
 
 tags = ["blog", "responsive", "clean", "light", "dark", "personal"]
 
@@ -20,8 +20,8 @@ features = [
     "search",
 ]
 
-min_version = "0.123.0"
+min_version = "0.154.0"
 
 [author]
-name = "Jimmy Cai"
-homepage = "https://jimmycai.com"
+    name     = "Jimmy Cai"
+    homepage = "https://jimmycai.com"