Remove support for generating dotkit files (#11986)

Dotkit is being used only at a few sites and has been deprecated on new
machines. This commit removes all the code that provide support for the
generation of dotkit module files.

A new validator named "deprecatedProperties" has been added to the
jsonschema validators. It permits to prompt a warning message or exit
with an error if a property that has been marked as deprecated is
encountered.

* Removed references to dotkit in the docs
* Removed references to dotkit in setup-env-test.sh
* Added a unit test for the 'deprecatedProperties' schema validator

var/spack/repos/builtin.mock/packages/override-module-templates/package.py

@@ -12,7 +12,6 @@ class OverrideModuleTemplates(Package):
 
     version('1.0', 'foobarbaz')
 
-    dotkit_template = 'override.txt'
     tcl_template = 'override.txt'
     lmod_template = 'override.txt'
 

var/spack/repos/builtin/packages/go/package.py

@@ -134,6 +134,6 @@ def setup_dependent_environment(self, spack_env, run_env, dependent_spec):
         # This *MUST* be first, this is where new code is installed
         spack_env.set('GOPATH', ':'.join(path_components))
 
-        # Allow packages to find this when using module or dotkit
+        # Allow packages to find this when using module files
         run_env.prepend_path('GOPATH', ':'.join(
             [dependent_spec.prefix] + path_components))