Add IP-Secure Routing support

[farmio]

Description

Add IP-Secure Routing support

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:

• The documentation has been adjusted accordingly
• Tests have been added that prove the fix is effective or that the feature works
• The changes are documented in the changelog (docs/changelog.md)

[codecov]

Codecov Report

Merging #1045 (5fa7f8b) into main (58348de) will decrease coverage by 0.06%.
The diff coverage is 94.52%.

@@            Coverage Diff             @@
##             main    #1045      +/-   ##
==========================================
- Coverage   96.42%   96.36%   -0.07%     
==========================================
  Files         138      138              
  Lines        8363     8577     +214     
==========================================
+ Hits         8064     8265     +201     
- Misses        299      312      +13     

Impacted Files	Coverage Δ
xknx/io/knxip_interface.py	85.16% <86.95%> (-0.03%)	⬇️
xknx/io/routing.py	90.55% <89.47%> (+1.07%)	⬆️
xknx/io/ip_secure.py	95.22% <95.22%> (ø)
xknx/io/connection.py	97.29% <100.00%> (+0.23%)	⬆️
xknx/io/tunnel.py	88.72% <100.00%> (ø)
xknx/secure/keyring.py	99.11% <100.00%> (+<0.01%)	⬆️

[marvin-w]

Looks good to me!

[farmio]

Cool! I'll try to add some tests before merging.