Lower precision for a number of queries.

These queries are currently run by default, but don't have their results displayed.

Looking through results on LGTM.com, they are either false positives (e.g., `BitwiseSignCheck` which flags many perfectly harmless operations and `CompareIdenticalValues` which mostly flags NaN checks) or harmless results that developers are unlikely to care about (e.g., `EmptyArrayInit` or `MisspelledIdentifier`).

With this PR, the only queries that are still run but not displayed are security queries, where different considerations may apply.

javascript/ql/src/NodeJS/CyclicImport.ql

@@ -8,7 +8,7 @@
  * @tags reliability
  *       maintainability
  *       frameworks/node.js
- * @precision medium
+ * @precision low
  */
 
 import javascript

javascript/ql/src/NodeJS/UnusedDependency.ql

@@ -3,7 +3,7 @@
  * @description If unnecessary package dependencies are included in package.json, the
  *              package will become harder to install.
  * @kind problem
- * @problem.severity warning
+ * @problem.severity recommendation
  * @id js/node/unused-npm-dependency
  * @tags maintainability
  *       frameworks/node.js