ci: added isort to pyproject.toml and pre-commit (#5933)

.pre-commit-config.yaml

@@ -39,4 +39,10 @@ repos:
   - id: actionlint-docker
     args: ["-ignore", "SC2102"]
 
+- repo: https://github.com/pycqa/isort
+  rev: 5.12.0
+  hooks:
+    - id: isort
+      name: isort (python)
+
 # TODO we can make pylint run at this stage too, once their execution gets normalized

pyproject.toml

@@ -246,6 +246,7 @@ formatting = [
   # Version specified following Black stability policy:
   # https://black.readthedocs.io/en/stable/the_black_code_style/index.html#stability-policy
   "black[jupyter]~=23.0",
+  "isort~=5.12"
 ]
 
 all = [
@@ -450,3 +451,5 @@ max-statements = 105  # Default is 50
 omit = [
     "haystack/testing/*",
 ]
+[tool.isort]
+profile = "black"