Streamlined eslint usage for eslint9 w/ cds8 (#719)

* Streamlined eslint usage

* import from @sap/cds instead of @sap/cds/lib

* Using @sap/cds/eslint.js

* eslint.config.mjs aktualisieren

* Adjusted eslint usage for eslint9 with cds8

bookshop/db/init.js

@@ -1,3 +1,5 @@
+const cds = require('@sap/cds')
+
 /**
  * In order to keep basic bookshop sample as simple as possible, we don't add
  * reuse dependencies. This db/init.js ensures we still have a minimum set of