Updated build instructions for Ubuntu 22.04+

[vlntb]

High Level Overview of Change

Recent Debian-based distributions (i.e. Ubuntu 22.04+) now restrict direct modifications to the system Python. To use an isolated system-wide install, one should use the pipx tool.

Context of Change

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)
• Refactor (non-breaking change that only restructures code)
• Performance (increase or change in throughput and/or latency)
• Tests (you added tests for code that already exists, or your new feature included in this PR)
• Documentation update
• Chore (no impact to binary, e.g. .gitignore, formatting, dropping support for older tooling)
• Release

API Impact

• Public API: New feature (new methods and/or new fields)
• Public API: Breaking change (in general, breaking changes should only impact the next api_version)
• libxrpl change (any change that may affect libxrpl or dependents of libxrpl)
• Peer protocol change (must be backward compatible or bump the peer protocol version)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.9%. Comparing base (43e1d44) to head (aa8c7ef).

Additional details and impacted files

@@            Coverage Diff            @@
##           develop   #5292     +/-   ##
=========================================
- Coverage     77.9%   77.9%   -0.0%     
=========================================
  Files          791     791             
  Lines        68007   68006      -1     
  Branches      8349    8350      +1     
=========================================
- Hits         52963   52959      -4     
- Misses       15044   15047      +3     

see 3 files with indirect coverage changes

[legleux]

Seems like a reasonable suggestion for adding Conan globally.