Add pre-commit configuration

'pre-commit' tool [1] provides an extensible way to configure hooks
which can be run automatically before each commit. That way we can make
sure that code send to review is passing base static analysis checks
like e.g. bandit, flake8 or hacking.

For now this is optional to use and not integrated in e.g. tox.ini file
but we can integrate it there too as next step.

[1] https://pre-commit.com/

Change-Id: I2338df66512e900a4cd04e9717cb19cc6ade48d2

.pre-commit-config.yaml

@@ -0,0 +1,38 @@
+---
+default_language_version:
+  # force all unspecified python hooks to run python3
+  python: python3
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.5.0
+    hooks:
+      - id: trailing-whitespace
+      - id: mixed-line-ending
+        args: ['--fix', 'lf']
+        exclude: '.*\.(svg)$'
+      - id: check-byte-order-marker
+      - id: check-executables-have-shebangs
+      - id: check-merge-conflict
+      - id: debug-statements
+      - id: check-yaml
+  - repo: https://github.com/lucas-c/pre-commit-hooks
+    rev: v1.5.4
+    hooks:
+      - id: remove-tabs
+        exclude: '.*\.(svg)$'
+  - repo: https://opendev.org/openstack/hacking
+    rev: 6.1.0
+    hooks:
+      - id: hacking
+        additional_dependencies: []
+        exclude: '^(doc|releasenotes|tools)/.*$'
+  - repo: local
+    hooks:
+      - id: flake8
+        name: flake8
+        additional_dependencies:
+          - hacking>=6.1.0,<6.2.0
+        language: python
+        entry: flake8
+        files: '^.*\.py$'
+        exclude: '^(doc|releasenotes|tools)/.*$'