Add IP-Secure tunnelling support

[farmio]

Description

Add IP-Secure tunnelling support.

This is work in progress:

• add necessary Frame parsers
• add parsing and decryption of knxkeys files
• verify knxkeys file with signature before using it
• add SearchRequestExtended support (not sure if this is needed yet)
• add SecureSession class (between Interface and Transport)
• add configuration options for needed parameters (passwords / keys)
• properly initiate SecureSession and keep it alive
• decrypt, verify and handle various encrypted KNXnet/IP frames
• properly react to various SessionStatus indications
• add tests... lots of tests

Fixes # (issue)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• I have performed a self-review of my own code
• The documentation has been adjusted accordingly
• The changes generate no new warnings
• Tests have been added that prove the fix is effective or that the feature works
• The changes are documented in the changelog
• The Homeassistant plugin has been adjusted in case of new config options

[codecov]

Codecov Report

Merging #875 (7a6db12) into main (fc71b01) will decrease coverage by 0.06%.
The diff coverage is 92.59%.

❗ Current head 7a6db12 differs from pull request most recent head 0d05e9c. Consider uploading reports for the commit 0d05e9c to get more accurate results

@@            Coverage Diff             @@
##             main     #875      +/-   ##
==========================================
- Coverage   95.50%   95.44%   -0.07%     
==========================================
  Files         116      121       +5     
  Lines        7013     7175     +162     
==========================================
+ Hits         6698     6848     +150     
- Misses        315      327      +12     

Impacted Files	Coverage Δ
xknx/knxip/session_status.py	84.00% <84.00%> (ø)
xknx/knxip/session_authenticate.py	91.66% <91.66%> (ø)
xknx/knxip/session_request.py	92.00% <92.00%> (ø)
xknx/knxip/session_response.py	92.30% <92.30%> (ø)
xknx/knxip/secure_wrapper.py	94.28% <94.28%> (ø)
xknx/knxip/__init__.py	100.00% <100.00%> (ø)
xknx/knxip/knxip.py	100.00% <100.00%> (ø)
xknx/knxip/knxip_enum.py	100.00% <100.00%> (ø)

[farmio]

superseded by #879 to use a feature branch https://github.com/XKNX/xknx/tree/ip-secure