[codespell] Adding Tox Target for Codespell

Second in a series of commits to add Codespell to Ironic Repos. This one adds the command that was used to fix the spelling errors.

Future Commits will add CI support and potentially a git-blame-ignore-revs file if their are lots of spelling mistakes that could clutter git blame.

Change-Id: Ie6d9f79138c39a530daeb471b2cf4a9bf19b5a98

setup.cfg

@@ -23,3 +23,8 @@ packages =
 # TODO(dtantsur): figure out a sane way to distribute tinyipa scripts
 data_files =
     share/ironic-python-agent-builder/dib = dib/*
+
+[codespell]
+quiet-level = 4
+# Words to ignore:
+# ignore-words-list = example

tox.ini

@@ -52,3 +52,13 @@ application-import-names = ironic_python_agent_builder
 # [H210] Require 'autospec', 'spec', or 'spec_set' in mock.patch/mock.patch.object calls
 # [H904] Delay string interpolations at logging calls.
 enable-extensions=H106,H203,H204,H205,H210,H904
+
+
+[testenv:codespell]
+description =
+  Run codespell to check spelling
+deps = codespell
+# note(JayF): {posargs} lets us run `tox -ecodespell -- -w` to get codespell
+#             to correct spelling issues in our code it's aware of.
+commands =
+  codespell {posargs}