New feature: table gutter

[Lucas-C]

Checklist:

• 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.

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (4afcf4c) 93.28% compared to head (31ba5d2) 93.29%.

❗ Current head 31ba5d2 differs from pull request most recent head ced1763. Consider uploading reports for the commit ced1763 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #787   +/-   ##
=======================================
  Coverage   93.28%   93.29%           
=======================================
  Files          27       27           
  Lines        7347     7355    +8     
  Branches     1329     1331    +2     
=======================================
+ Hits         6854     6862    +8     
  Misses        309      309           
  Partials      184      184           

Impacted Files	Coverage Δ
fpdf/fpdf.py	92.54% <100.00%> (ø)
fpdf/table.py	92.55% <100.00%> (+0.28%)	⬆️

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[Lucas-C]

@gmischler @MartinThoma: would you like to review this new feature?

I'd be happy to have you opinion on this😊

[kuth-chi]

Great to get this.

[Lucas-C]

OK I'm merginh this