Improve compatibility with pathlib by implementing more common methods

[pjbull]

Contributor PR of #230 to run the live tests.

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• Added absolute, resolve and relative_to implementations

• Added tests interacting with PurePosixPaths

• Added is_absolute and is_relative_to as well

• Accept read_text parameters

• Added exist_ok paramter to touch

• Added missing_ok paramter to unlink

• Fixed formatting (make format)

• Update history.md & readme.md

• Fix relative_to on different providers (+ some naming changes

• Reformat

• Update history.md and bump version number to 0.9

• Update dev requirements for docs

• Fix readme list order

• Added test for relative_to on different provider cloud paths

• Remove unused import

• Updated relative_to different cloud test

[github-actions]

🚀 Deployed on https://deploy-preview-232--gallant-agnesi-5f7bb3.netlify.app

[codecov-commenter]

Codecov Report

Merging #232 (6360893) into master (da86719) will increase coverage by 0.1%.
The diff coverage is 98.2%.

@@           Coverage Diff            @@
##           master    #232     +/-   ##
========================================
+ Coverage    94.7%   94.8%   +0.1%     
========================================
  Files          21      21             
  Lines        1287    1323     +36     
========================================
+ Hits         1219    1255     +36     
  Misses         68      68             

Impacted Files	Coverage Δ
cloudpathlib/cloudpath.py	93.5% <96.0%> (+0.2%)	⬆️
cloudpathlib/azure/azblobclient.py	94.3% <100.0%> (+0.1%)	⬆️
cloudpathlib/azure/azblobpath.py	92.7% <100.0%> (+0.2%)	⬆️
cloudpathlib/client.py	87.9% <100.0%> (ø)
cloudpathlib/gs/gsclient.py	94.6% <100.0%> (+0.1%)	⬆️
cloudpathlib/gs/gspath.py	94.1% <100.0%> (+0.2%)	⬆️
cloudpathlib/local/localclient.py	96.5% <100.0%> (+0.1%)	⬆️
cloudpathlib/local/localpath.py	94.4% <100.0%> (ø)
cloudpathlib/s3/s3client.py	95.5% <100.0%> (+<0.1%)	⬆️
cloudpathlib/s3/s3path.py	97.9% <100.0%> (+<0.1%)	⬆️