feat(providers): add conftest providers

`conftest` is a handy provider for applying policies on your config
files. You can use the `conftest` provider and module type directly
to manually configure your tests, or you can use the "generator"
providers `conftest-container` and `conftest-kubernetes` to
automatically generate conftest modules. The former creates one test
for each `container` module in your project (very similar to the
`hadolint` provider), and the latter does the same for each `kubernetes`
and `helm` module in your project.

docs/README.md

@@ -32,14 +32,20 @@
   * [Commands Reference](./reference/commands.md)
   * [Config Files Reference](./reference/config.md)
   * [Module Types](./reference/module-types/README.md)
+    * [Conftest](./reference/module-types/conftest.md)
     * [Container](./reference/module-types/container.md)
     * [Exec](./reference/module-types/exec.md)
+    * [Hadolint](./reference/module-types/hadolint.md)
     * [Helm](./reference/module-types/helm.md)
     * [Kubernetes](./reference/module-types/kubernetes.md)
     * [Maven Container](./reference/module-types/maven-container.md)
     * [Openfaas](./reference/module-types/openfaas.md)
     * [Terraform](./reference/module-types/terraform.md)
   * [Providers](./reference/providers/README.md)
+    * [Conftest](./reference/providers/conftest.md)
+    * [Conftest Container](./reference/providers/conftest-container.md)
+    * [Conftest Kubernetes](./reference/providers/conftest-kubernetes.md)
+    * [Hadolint](./reference/providers/hadolint.md)
     * [Kubernetes](./reference/providers/kubernetes.md)
     * [Local Kubernetes](./reference/providers/local-kubernetes.md)
     * [Maven Container](./reference/providers/maven-container.md)

docs/reference/module-types/README.md

@@ -7,6 +7,8 @@ title: Module Types
 
 * [Exec](./exec.md)
 * [Container](./container.md)
+* [Conftest](./conftest.md)
+* [Hadolint](./hadolint.md)
 * [Helm](./helm.md)
 * [Kubernetes](./kubernetes.md)
 * [Maven Container](./maven-container.md)