use reactive breakpoints to conditionally render right sidebar

+ use reactive content div width to remove big img on album page header

src/composables/useBreakpoints.ts

@@ -0,0 +1,7 @@
+import { useBreakpoints, breakpointsTailwind } from "@vueuse/core";
+
+const breakpoints = useBreakpoints(breakpointsTailwind);
+
+const xl = breakpoints.greater("xl");
+
+export { xl };