CCT-266: Update TLS flags

[m-horky]

• Card ID: CCT-266

• The flag PROTOCOL_SSLv23 is an alias to PROTOCOL_TLS since Python 3.6.
• The flag PROTOCOL_TLS is deprecated since Python 3.10.
• The flag PROTOCOL_TLS_CLIENT has been introduced in Python 3.6 and should be used for client-side contexts.

This patch uses PROTOCOL_TLS_CLIENT instead of PROTOCOL_SSLv23.

• There is no need to use OP_NO_SSLv2 and OP_NO_SSLv3 flags explicitly now; SSLContext disables these by default.

• The flag PROTOCOL_TLS_CLIENT enables the check_hostname by default. For insecure contexts we need to disable this flag explicitly.

[github-actions]

Coverage (computed on Fedora latest) •

File	Stmts	Miss	Cover	Missing
rhsm
connection.py	1016	461	54%	48–49, 53, 55–56, 81, 101–102, 109, 150, 284, 315, 381–386, 390–399, 460, 462, 564, 567, 574–580, 641, 676–680, 682, 695, 722, 725–726, 728–729, 731, 742–746, 750, 754, 756–757, 776, 779, 783–784, 789, 792–793, 808, 812, 814–815, 842–843, 845, 848, 853–854, 857–858, 860, 862–866, 868–869, 872–879, 881–891, 893, 895–896, 907–909, 911–913, 915–917, 919–921, 923, 926–932, 934–935, 937–938, 940, 951–953, 955–956, 958–960, 962, 974–977, 982, 1046, 1048–1053, 1055, 1060–1064, 1070–1073, 1075–1080, 1084–1089, 1096, 1133, 1135, 1140, 1151, 1160–1163, 1167, 1169–1171, 1175–1176, 1178–1185, 1187, 1189, 1192–1199, 1202–1203, 1208, 1210, 1260, 1277–1280, 1304, 1326, 1356, 1361, 1364, 1367–1368, 1373, 1376, 1381, 1384, 1427–1431, 1438–1439, 1441, 1449–1450, 1452, 1469, 1482–1484, 1487, 1500, 1507, 1511, 1539–1541, 1546–1547, 1549–1550, 1552–1553, 1555–1569, 1571–1573, 1575–1586, 1588, 1605–1607, 1609–1611, 1613–1615, 1620, 1625–1627, 1632, 1659, 1691–1719, 1724–1725, 1727–1729, 1732–1733, 1736–1737, 1740–1741, 1760–1761, 1770–1771, 1781–1782, 1789–1790, 1796–1799, 1805–1808, 1814–1815, 1821–1822, 1842–1843, 1852–1856, 1864–1865, 1891–1894, 1919–1920, 1929–1930, 1938–1939, 1960, 1962–1964, 1966, 1968, 1971, 1973–1986, 1988–1989, 1998–2000, 2012–2013, 2022–2023, 2025, 2027–2029, 2036–2038, 2047–2049, 2057–2058, 2069, 2071–2072, 2074, 2076–2079, 2081–2083, 2086, 2088, 2095–2096, 2103–2104, 2114–2115, 2125–2128, 2138–2144, 2151–2154
TOTAL	18221	4609	74%

Tests	Skipped	Failures	Errors	Time
2640	14 💤	0 ❌	0 🔥	43.354s ⏱️

[jirihnidek]

LGTM