Create default pre-commit-config.yaml when missing

This commit makes a few small fixes, but is primarily intended to fix
an issue with "make pre-commit" when .pre-commit-config.yaml file
isn't present.

makefiles/commands/pre-commit/pre-commit.mk
-------------------------------------------
  o Depend on target pre-commit-install VS venv.
  o Virtualenv target requirements.txt config lacks package pre-commit.

makefiles/commands/pre-commit/install.mk
----------------------------------------
  o Fixed requirements.txt path typo:
    + Copy pre-c/requirements.txt VS tox/requirements.txt.
    + Contributed to variant target behavior when used in a prisine/cloned sandbox.
      targets: pre-commit VS pre-commit-install
  o Define installer target and path vars containing .pre-commit-config.yaml
    so a default tool config file can be installed.

.gitreview
bin/setup.sh
------------
  o Cleanup a few pre-commit complaints in source.

Signed-off-by: Eric Ball <eball@linuxfoundation.org>
Change-Id: I03843c906798036a32a45e965d4c1a9cdd72be8b
diff --git a/.gitreview b/.gitreview
index 0175bce..48e0f99 100644
--- a/.gitreview
+++ b/.gitreview
@@ -27,4 +27,4 @@
 defaultremote=origin
 defaultbranch=master
 
-# [EOF]
\ No newline at end of file
+# [EOF]