MAINT: Remove b_ and str_

[pubpub-zz]

closes #2726
superseed proposal #2791

[stefan6419846]

Could you please provide some further rationale for this change?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.26%. Comparing base (5abd590) to head (6eeac53).
Report is 73 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2792      +/-   ##
==========================================
+ Coverage   95.16%   95.26%   +0.09%     
==========================================
  Files          51       51              
  Lines        8545     8535      -10     
  Branches     1703     1700       -3     
==========================================
- Hits         8132     8131       -1     
+ Misses        261      252       -9     
  Partials      152      152              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[pubpub-zz]

after analysis, most of the b_ were required due to StreamObjects. I've fixed the cases where a string was generated instead of bytes. some operators from operations were inserted as text instead of string.I've also refactored some functions to try to improve performances.
read_string_from_stream was partially rewritten. now the r"c:\DEB\3368" is converted into b"c:\DEB\3368" instead of "C:DEBÆł8". This is for me another way to interprete pypdf spec 1.7 p54. and which I currently prefer
The change in expected file Seige_of_Vicksburg_Sample_OCR-crazyones-merged.pdf is a space which is written as " " instead of \040 (which is the octal code of 32)

there is still a little of work for coverage (under analysis) but @stefan6419846 / @j-t-1 waiting for your comments

[j-t-1]

This is a win. These kinds of improvements make pypdf more readable, understandable and extensible.

[pubpub-zz]

test coverage is good now.