chore(sider): add sider default config for flake8 + ignore tab errors (W191) (bp #12587) (#12598)

Co-authored-by: Mohammad Hasnain Mohsin Rajan <hasnain2808@gmail.com>

.flake8

@@ -0,0 +1,32 @@
+[flake8]
+ignore =
+    E121,
+    E126,
+    E127,
+    E128,
+    E203,
+    E225,
+    E226,
+    E231,
+    E241,
+    E251,
+    E261,
+    E265,
+    E302,
+    E303,
+    E305,
+    E402,
+    E501,
+    E741,
+    W291,
+    W292,
+    W293,
+    W391,
+    W503,
+    W504,
+    F403,
+    B007,
+    B950,
+    W191,
+
+max-line-length = 200

sider.yml

@@ -0,0 +1,3 @@
+linter:
+  flake8:
+    config: .flake8