chore: switched to new build system for css.

- added community.bundle.less file to create css bundle
- removed the obsolete build.json in favor of new build system
- updated the paths in the books
- removed the imported urls from css files (the new build system doesn't support that)
- removed obsolete lms.css

community/public/css/style.less

@@ -1,9 +1,4 @@
 @primary-color: #08B74F;
-@import url('https://rsms.me/inter/inter.css');
-
-body {
-  font-family: "Inter", sans-serif;
-}
 
 h2 {
   margin: 20px 0px;