Remove parsl-specific stuff from flake8

Unrelated, but some cleanup before moving forward

.flake8

@@ -1,23 +1 @@
-[flake8]
-# D203: 1 blank line required before class docstring
-# E124: closing bracket does not match visual indentation
-# E126: continuation line over-indented for hanging indent
-# This one is bad. Sometimes ordering matters, conditional imports
-# setting env vars necessary etc.
-# E402: module level import not at top of file
-# E129: Visual indent to not match indent as next line, counter eg here:
-# https://github.com/PyCQA/pycodestyle/issues/386
-# W504: line break after binary operator
-#       (Raised by flake8 even when it is followed)
-ignore = D203, E124, E126, E402, E129, W504
 max-line-length = 160
-exclude = parsl/executors/serialize/, test_import_fail.py
-# E741 disallows ambiguous single letter names which look like numbers
-# We disable it in visualization code because plotly uses 'l' as
-# a keyword arg
-# F821: undefined name
-per-file-ignores = parsl/monitoring/visualization/*:E741,
-  # needed because this deliberately has undefined names in it
-  parsl/tests/test_swift.py:F821,
-  # test_ssh_errors.py really is broken
-  parsl/tests/integration/test_channels/test_ssh_errors.py:F821