Removed unnecessary themes

.gitmodules

@@ -1,12 +1,3 @@
-[submodule "themes/hyde-hyde"]
-	path = themes/hyde-hyde
-	url = https://github.com/htr3n/hyde-hyde.git
-[submodule "themes/terminal"]
-	path = themes/terminal
-	url = https://github.com/panr/hugo-theme-terminal.git
-[submodule "themes/book"]
-	path = themes/book
-	url = https://github.com/alex-shpak/hugo-book
 [submodule "themes/fuji"]
 	path = themes/fuji
 	url = https://github.com/amzrk2/hugo-theme-fuji.git