Draft: page label feature

[andersonhc]

Implements "Page label" feature in fpdf2.

Checklist:

• [x] Implement page label

• [x] Create method to read page labels if the user wants to use on header, footer, etc.

• [ ] Add option on TOC to list page labels instead of page number

• [ ] The GitHub pipeline is OK (green), meaning that both pylint (static code analyzer) and black (code formatter) are happy with the changes of this PR.

• [ ] A unit test is covering the code added / modified by this PR

• [ ] This PR is ready to be merged

• [ ] In case of a new feature, docstrings have been added, with also some documentation in the docs/ folder

• [ ] A mention of the change is present in CHANGELOG.md

By submitting this pull request, I confirm that my contribution is made under the terms of the GNU LGPL 3.0 license.

[Lucas-C]

This is really promising, good job @andersonhc 👍 🙂

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 67.88991% with 35 lines in your changes missing coverage. Please review.

Project coverage is 92.96%. Comparing base (2b866d8) to head (56aa6c9). Report is 27 commits behind head on master.

:exclamation: Current head 56aa6c9 differs from pull request most recent head d1346c6

Please upload reports for the commit d1346c6 to get more accurate results.

Files	Patch %	Lines
fpdf/fpdf.py	44.44%	25 Missing :warning:
fpdf/output.py	81.08%	5 Missing and 2 partials :warning:
fpdf/util.py	62.50%	3 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1188      +/-   ##
==========================================
- Coverage   93.25%   92.96%   -0.29%     
==========================================
  Files          30       31       +1     
  Lines        9253     9699     +446     
  Branches     2104     2171      +67     
==========================================
+ Hits         8629     9017     +388     
- Misses        385      432      +47     
- Partials      239      250      +11     

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[Lucas-C]

Also, a minor detail: I think this PR removes execution rights on scripts/compare-changed-pdfs.py

[andersonhc]

I think this is ready to be merged whenever you want @andersonhc 🙂

I am just waiting #1300 so I can rebase and merge after him