Fix Salt warnings and testuite for Python 3.11 (#635)

* Switch to `FullArgSpec` since Py 3.11 no longer has `ArgSpec`, deprecated since Py 3.0

Signed-off-by: Pedro Algarvio <[email protected]>

* Backport `locale.getdefaultlocale()` into Salt. It's getting removed in Py 3.13

Signed-off-by: Pedro Algarvio <[email protected]>

* Stop using the deprecated `pipes` module

Signed-off-by: Pedro Algarvio <[email protected]>

* Stop using the deprecated `cgi` module.

Signed-off-by: Pedro Algarvio <[email protected]>

* Add `__getstate__` to blacklisted methods, present in Py 3.11

Signed-off-by: Pedro Algarvio <[email protected]>

* Fix test_state test

* Use proper keys since Python's base64 in Py3.11 is more picky

```
❯ artifacts/salt/bin/python3
Python 3.10.11 (main, May  5 2023, 02:31:54) [GCC 11.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import base64
>>> base64.b64decode("AAAAB3NzaC1kcQ9J5bYTEyZ==", validate=True)
b'\x00\x00\x00\x07ssh-dq\x0fI\xe5\xb6\x13\x13&'
```
```
$ artifacts/salt/bin/python3
Python 3.11.3 (main, May  5 2023, 02:31:40) [GCC 11.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import base64
>>> base64.b64decode("AAAAB3NzaC1kcQ9J5bYTEyZ==", validate=True)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/tmp/testing/artifacts/salt/lib/python3.11/base64.py", line 88, in b64decode
    return binascii.a2b_base64(s, strict_mode=validate)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
binascii.Error: Excess data after padding
```

Signed-off-by: Pedro Algarvio <[email protected]>

---------

Signed-off-by: Pedro Algarvio <[email protected]>
Co-authored-by: Pedro Algarvio <[email protected]>
Co-authored-by: Marek Czernek <[email protected]>

tests/pytests/unit/modules/state/test_state.py

@@ -593,7 +593,7 @@ def test_show_states_missing_sls():
     chunks_mock = MagicMock(side_effect=[msg])
     mock = MagicMock(side_effect=["A", None])
     with patch.object(state, "_check_queue", mock), patch(
-        "salt.state.HighState.compile_low_chunks", chunks_mock
+        "salt.modules.state.salt.state.HighState.compile_low_chunks", chunks_mock
     ):
         assert state.show_low_sls("foo") == "A"
         assert state.show_states("foo") == [msg[0]]