QL: restrict the queries that are run by default

Author: esbena

ql/src/codeql-suites/ql-all.qls

@@ -0,0 +1,8 @@
+- description: All Code Scanning queries for QL
+- queries: .
+- include:
+    kind:
+    - problem
+    - path-problem
+    - alert
+    - path-alert

ql/src/codeql-suites/ql-code-scanning.qls

@@ -6,3 +6,13 @@
     - path-problem
     - alert
     - path-alert
+    precision:
+    - high
+    - very-high
+    problem.severity:
+    - error
+    - warning
+- exclude:
+    deprecated: //
+- exclude:
+    query path: /^experimental\/.*/

ql/src/queries/style/ImplicitThis.ql

@@ -2,7 +2,7 @@
  * @name Using implicit `this`
  * @description Writing member predicate calls with an implicit `this` can be confusing
  * @kind problem
- * @problem.severity warning
+ * @problem.severity recommendation
  * @precision very-high
  * @id ql/implicit-this
  * @tags maintainability