[pre-commit] Update configurations

- Add isort
- Update black repository reference
- Add ast check and case conflict check

Update flake8 configuration for line
length to match the one from black.

.flake8

 [flake8]
-max-line-length = 80
+max-line-length = 88
 select = B,C,E,F,W,T4,B9,B950
-ignore = E501, W503
+ignore = E501, W503, E203

.isort.cfg

+[settings]
+line_length=88
+order_by_type=true
+lines_between_types=1

.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
+  - repo: https://github.com/timothycrosley/isort
+    rev: 4.3.21-2
+    hooks:
+    - id: isort
+      args: [-sl]
+  - repo: https://github.com/psf/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
+      - id: black
+        exclude: beat/backend/python/test/prefix/.*/syntax_error
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v2.0.0
     hooks:
+      - id: check-ast
+        exclude: beat/backend/python/test/prefix/.*/syntax_error
+      - id: check-case-conflict
       - 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
+        exclude: beat/backend/python/test/prefix/.*/syntax_error
       - id: check-added-large-files
       - id: check-docstring-first
       - id: flake8
+        exclude: beat/backend/python/test/prefix/.*/(.*crash|syntax_error)
       - 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
+        exclude: beat/backend/python/test/prefix/.*/syntax_error
   - repo: local
     hooks:
       - id: sphinx-build