[pre-commit] Add pre-commit related configuration files

.flake8

+[flake8]
+max-line-length = 80
+select = B,C,E,F,W,T4,B9,B950
+ignore = E501, W503

.pre-commit-config.yaml

+# See https://pre-commit.com for more information
+# See https://pre-commit.com/hooks.html for more hooks
+repos:
+  - repo: https://github.com/ambv/black
+    rev: stable
+    hooks:
+    - id: black
+      language_version: python3.6
+      exclude: beat/core/test/prefix/algorithms/user/syntax_error/1.py|beat/core/test/prefix/databases/invalid/1.py
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v2.0.0
+    hooks:
+      - id: trailing-whitespace
+      - id: end-of-file-fixer
+      - id: debug-statements
+        exclude: beat/core/test/prefix/algorithms/user/syntax_error/1.py|beat/core/test/prefix/databases/invalid/1.py
+      - id: check-added-large-files
+      - id: check-docstring-first
+      - id: flake8
+      - id: check-yaml
+        exclude: conda/meta.yaml
+  - repo: https://github.com/PyCQA/bandit
+    rev: 'master' # Update me!
+    hooks:
+      - id: bandit
+        exclude: beat/editor/test|beat/core/test/prefix/algorithms/user/syntax_error/1.py|beat/core/test/prefix/databases/invalid/1.py
+  - repo: local
+    hooks:
+      - id: sphinx-build
+        name: sphinx build
+        entry: python -m sphinx.cmd.build
+        args: [-a, -E, -W, doc, sphinx]
+        language: system
+        files: ^doc/
+        types: [file]
+        pass_filenames: false
+      - id: sphinx-doctest
+        name: sphinx doctest
+        entry: python -m sphinx.cmd.build
+        args: [-a, -E, -b, doctest, doc, sphinx]
+        language: system
+        files: ^doc/
+        types: [file]
+        pass_filenames: false