Allow the codeql-action to run packages

This commit adds a `packs` option to the codeql-config.yml file. Users
can specify a list of ql packs to include in the analysis.

For a single language analysis, the packs property looks like this:

```yaml
packs:
  - pack-scope/pack-name1@1.2.3
  - pack-scope/pack-name2   # no explicit version means download the latest
```

For multi-language analysis, you must key the packs block by lanaguage:

```yaml
packs:
  cpp:
    - pack-scope/pack-name1@1.2.3
    - pack-scope/pack-name2
  java:
    - pack-scope/pack-name3@1.2.3
    - pack-scope/pack-name4
```

This implementation adds a new analysis run (alongside custom and 
builtin runs). The unit tests indicate that the correct commands are
being run, but I have not actually tried this with a real CLI.

Also, convert `instanceof Array` to `Array.isArray` since that is
sightly better in some situations. See:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/isArray#instanceof_vs_isarray

node_modules/.package-lock.json

@@ -405,6 +405,12 @@
         "@types/node": "*"
       }
     },
+    "node_modules/@types/js-yaml": {
+      "version": "4.0.1",
+      "resolved": "https://registry.npmjs.org/@types/js-yaml/-/js-yaml-4.0.1.tgz",
+      "integrity": "sha512-xdOvNmXmrZqqPy3kuCQ+fz6wA0xU5pji9cd1nDrflWaAWtYLLGk5ykW0H6yg5TVyehHP1pfmuuSaZkhP+kspVA==",
+      "dev": true
+    },
     "node_modules/@types/json-schema": {
       "version": "7.0.6",
       "dev": true,
@@ -1253,6 +1259,7 @@
       "dependencies": {
         "anymatch": "~3.1.1",
         "braces": "~3.0.2",
+        "fsevents": "~2.1.2",
         "glob-parent": "~5.1.0",
         "is-binary-path": "~2.1.0",
         "is-glob": "~4.0.1",
@@ -3238,6 +3245,9 @@
     "node_modules/jsonfile": {
       "version": "4.0.0",
       "license": "MIT",
+      "dependencies": {
+        "graceful-fs": "^4.1.6"
+      },
       "optionalDependencies": {
         "graceful-fs": "^4.1.6"
       }