add initial flake8 config

flake8 configuration file supress warnings, that can be fixed later.
Supressed warnings can be splitted for three categories and for each of them
separate issue exists:

- Fix warnings Exx: #5599
- Fix warnings Fxx: #5598
- Fix warnings Wxx: #5597

.flake8

@@ -0,0 +1,66 @@
+[flake8]
+inline-quotes = "
+statistics = True
+select = Q0
+exclude = test/test-run.py
+ignore =
+    # E111: indentation is not a multiple of four
+    E111,
+    # E123: closing bracket does not match indentation of opening bracket's line
+    E123,
+    # E126: continuation line over-indented for hanging indent
+    E126,
+    # E128: continuation line under-indented for visual indent
+    E128,
+    # E201: whitespace after '('
+    E201,
+    # E202: whitespace before ')'
+    E202,
+    # E203: whitespace before ':'
+    E203,
+    # E225: missing whitespace around operator
+    E225,
+    # E226: missing whitespace around arithmetic operator
+    E226,
+    # E231: missing whitespace after ',', ';' or ':'
+    E231,
+    # E241: multiple spaces after ','
+    E241,
+    # E251: unexpected spaces around keyword / parameter equals
+    E251,
+    # E261: at least two spaces before inline comment
+    E261,
+    # E265: block comment should start with '#'
+    E265,
+    # E266: too many leading '#' for block comment
+    E266,
+    # E302: expected 2 blank lines, found 0
+    E302,
+    # E305: expected 2 blank lines after end of function or class
+    E305,
+    # E402: module level import not at top of file
+    E402,
+    # E501: line too long (82 > 79 characters)
+    E501,
+    # E502: the backslash is redundant between brackets
+    E502,
+    # E703: statement ends with a semicolon
+    E703,
+    # E722: do not use bare except, specify exception instead
+    E722,
+    # F401: module imported but unused
+    F401,
+    # F403: 'from module import *' used; unable to detect undefined names
+    F403,
+    # F405: name may be undefined, or defined from star imports: module
+    F405,
+    # F821: undefined name name
+    F821,
+    # F841: local variable name is assigned to but never used
+    F841,
+    # W291: trailing whitespace
+    W291,
+    # W391: blank line at end of file
+    W391,
+    # W605: invalid escape sequence 'x'
+    W605