bpo-38116: Convert select module to PEP-384

[DinoV]

Summary: Do the necessary versions to be PEP-384 compatible , including migrating PyType_Ready to PyType_FromSpec and moving static data into a new _selectstate struct.

https://bugs.python.org/issue38116

[tiran]

macOS build fails:

gcc -Wno-unused-result -Wsign-compare -g -O0 -Wall -std=c99 -Wextra -Wno-unused-result -Wno-unused-parameter -Wno-missing-field-initializers -Wstrict-prototypes -Werror=implicit-function-declaration -I./Include/internal -I./Include -I. -I/usr/local/include -I/Users/vsts/agent/2.155.1/work/1/s/Include -I/Users/vsts/agent/2.155.1/work/1/s -c /Users/vsts/agent/2.155.1/work/1/s/Modules/selectmodule.c -o build/temp.macosx-10.14-x86_64-3.9-pydebug/Users/vsts/agent/2.155.1/work/1/s/Modules/selectmodule.o
/Users/vsts/agent/2.155.1/work/1/s/Modules/selectmodule.c:1924:17: warning: initializing 'void *' with an expression of type 'const char [671]' discards qualifiers [-Wincompatible-pointer-types-discards-qualifiers]
    {Py_tp_doc, kqueue_event_doc},
                ^~~~~~~~~~~~~~~~
In file included from /Users/vsts/agent/2.155.1/work/1/s/Modules/selectmodule.c:2274:
/Users/vsts/agent/2.155.1/work/1/s/Modules/clinic/selectmodule.c.h:962:19: error: use of undeclared identifier 'kqueue_queue_Type'
    if ((type == &kqueue_queue_Type) &&
                  ^
/Users/vsts/agent/2.155.1/work/1/s/Modules/clinic/selectmodule.c.h:966:19: error: use of undeclared identifier 'kqueue_queue_Type'
    if ((type == &kqueue_queue_Type) &&
                  ^
/Users/vsts/agent/2.155.1/work/1/s/Modules/selectmodule.c:2443:17: error: use of undeclared identifier 'kqueue_queue_doc'
    {Py_tp_doc, kqueue_queue_doc},
                ^
/Users/vsts/agent/2.155.1/work/1/s/Modules/selectmodule.c:2446:17: error: use of undeclared identifier 'kqueue_queue_new'
    {Py_tp_new, kqueue_queue_new},
                ^
1 warning and 4 errors generated.

[bedevere-bot]

When you're done making the requested changes, leave the comment: I have made the requested changes; please review again.

[DinoV]

I have made the requested changes; please review again.

[bedevere-bot]

Thanks for making the requested changes!

@tiran: please review the changes made to this pull request.

[bedevere-bot]

@DinoV: Please replace # with GH- in the commit message next time. Thanks!