Remove unused themes

.gitmodules

@@ -1,18 +1,3 @@
 [submodule "themes/ananke"]
 	path = themes/ananke
 	url = https://github.com/budparr/gohugo-theme-ananke.git
-[submodule "themes/bootstrap4"]
-	path = themes/hugo-theme-bootstrap4-blog
-	url = https://github.com/alanorth/hugo-theme-bootstrap4-blog.git
-[submodule "themes/hyde-hyde"]
-	path = themes/hyde-hyde
-	url = https://github.com/htr3n/hyde-hyde.git
-[submodule "themes/hugo-theme-jane"]
-	path = themes/hugo-theme-jane
-	url = https://github.com/xianmin/hugo-theme-jane.git
-[submodule "themes/uBlogger"]
-	path = themes/uBlogger
-	url = https://github.com/upagge/uBlogger.git
-[submodule "themes/accessible-minimalism"]
-	path = themes/accessible-minimalism
-	url = https://github.com/leonstafford/accessible-minimalism-hugo-theme