Add packs and queries from input

This commit adds the packs and queries from the actions input to the
config file used by the CodeQL CLI.

When the `+` is used, the actions input value is combined with the
config value and when it is not used, the input value overrides the
config value.

This commit also adds a bunch of integration tests for this feature.
In order to avoid adding too many new jobs, all of the tests are
run sequentially in a single job (matrixed across relevant operating
systems and OSes).

tests/multi-language-repo/.github/codeql/codeql-config-packaging.yml

@@ -6,9 +6,6 @@ packs:
     - dsp-testing/codeql-pack1@1.0.0
     - dsp-testing/codeql-pack2
     - dsp-testing/codeql-pack3:other-query.ql
-  ruby:
-    - dsp-testing/hucairz
-    - dsp-testing/i-dont-exist@1.0.0
 
 paths-ignore:
   - tests

tests/multi-language-repo/.github/codeql/multi-language-packs-config.yml

@@ -0,0 +1,9 @@
+packs:
+  javascript:
+    - dsp-testing/codeql-pack1@1.0.0
+    - dsp-testing/codeql-pack2
+  ruby:
+    - codeql/ruby-queries
+
+queries:
+  - uses: ./codeql-qlpacks/complex-javascript-qlpack/foo2/show_ifs.ql

tests/multi-language-repo/.github/codeql/other-config-properties.yml

@@ -0,0 +1,9 @@
+name: Config using all properties
+
+disable-default-queries: true
+
+paths-ignore:
+  - xxx
+
+paths:
+  - yyy

tests/multi-language-repo/.github/codeql/queries-and-packs-config.yml

@@ -0,0 +1,7 @@
+packs:
+  javascript:
+    - dsp-testing/codeql-pack1@1.0.0
+    - dsp-testing/codeql-pack2
+
+queries:
+  - uses: ./codeql-qlpacks/complex-javascript-qlpack/foo2/show_ifs.ql