pre-commit: ship default and full configs (#28463)

For now, the only difference between the two is mypy.

.pre-commit-config.yaml

@@ -1,3 +1,10 @@
+# This configuration includes the default, minimal set of hooks to be
+# run on all commits. It requires no specific setup and one can just
+# start using pre-commit with it.
+#
+# See .pre-commit-config-all.yaml for a more complete one that comes
+# with a better coverage at the cost of some specific setup needed.
+
 repos:
 -   repo: https://github.com/psf/black
     rev: 19.10b0
@@ -15,17 +22,3 @@ repos:
           - flake8-docstrings==1.3.1
           - pydocstyle==4.0.0
         files: ^(homeassistant|script|tests)/.+\.py$
-# Using a local "system" mypy instead of the mypy hook, because its
-# results depend on what is installed. And the mypy hook runs in a
-# virtualenv of its own, meaning we'd need to install and maintain
-# another set of our dependencies there... no. Use the "system" one
-# and reuse the environment that is set up anyway already instead.
--   repo: local
-    hooks:
-    -   id: mypy
-        name: mypy
-        entry: mypy
-        language: system
-        types: [python]
-        require_serial: true
-        files: ^homeassistant/.+\.py$