Run all linters via pre-commit

Executes all linters via pre-commit, which is much faster, guarantees
their version locking and allows upgrading them with a single command.

Before this change the only linter running via pre-commit was
ansible-lint.

Now we also run bashate, flake8 and yamllint via pre-commit.

For developer convenience we still keep the old tox environments
which allow running a single linter.

Added long_description_content_type to fix twine check failure

Change-Id: I037eae61921b2a84aa99838804f70e96ee8d8b13

.pre-commit-config.yaml

@@ -0,0 +1,40 @@
+---
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v2.1.0
+    hooks:
+      - id: end-of-file-fixer
+      - id: trailing-whitespace
+      - id: mixed-line-ending
+      - id: check-byte-order-marker
+      - id: check-executables-have-shebangs
+      - id: check-merge-conflict
+      - id: debug-statements
+      - id: flake8
+      - id: check-yaml
+        files: .*\.(yaml|yml)$
+  - repo: https://github.com/adrienverge/yamllint.git
+    rev: v1.15.0
+    hooks:
+      - id: yamllint
+        files: \.(yaml|yml)$
+        types: [file, yaml]
+        entry: yamllint --strict -f parsable
+  - repo: https://github.com/ansible/ansible-lint
+    rev: v4.1.0a0
+    hooks:
+      - id: ansible-lint
+        files: \.(yaml|yml)$
+        entry: ansible-lint --force-color -v
+  - repo: https://github.com/openstack-dev/bashate.git
+    rev: 0.6.0
+    hooks:
+      - id: bashate
+        entry: bashate --error . --verbose --ignore=E006,E040
+        # Run bashate check for all bash scripts
+        # Ignores the following rules:
+        # E006: Line longer than 79 columns (as many scripts use jinja
+        #       templating, this is very difficult)
+        # E040: Syntax error determined using `bash -n` (as many scripts
+        #       use jinja templating, this will often fail and the syntax
+        #       error will be discovered in execution anyway)