Pharo13 + other development improvements

[jbrichau]

• Fixes the removal of the Author class in Pharo 13
• Moves the Seaside control panel to it's own main menu
• Adds the selenium setup for development (on Mac only for now)

This is a draft. Need to finish some things.

[codecov]

Codecov Report

Attention: Patch coverage is 9.75610% with 37 lines in your changes missing coverage. Please review.

Project coverage is 49.44%. Comparing base (0f7d6f7) to head (39a3a9a).
Report is 4 commits behind head on master.

Files with missing lines	Patch %	Lines
...class/runSeleniumServerInTerminalMenuCommandOn..st	0.00%	9 Missing ⚠️
...oControlPanel.class/class/seasideMenuCommandOn..st	0.00%	7 Missing ⚠️
...olPanel.class/class/runSeleniumServerInTerminal.st	0.00%	6 Missing ⚠️
...ntrolPanel.class/class/seasideIcebergRepository.st	0.00%	6 Missing ⚠️
...rolPanel.class/class/controlPanelMenuCommandOn..st	0.00%	4 Missing ⚠️
...atform.extension/instance/seasideSetAuthorName..st	0.00%	3 Missing ⚠️
...velopment.class/class/ensureAuthorInitialsWith..st	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1450      +/-   ##
==========================================
+ Coverage   49.42%   49.44%   +0.02%     
==========================================
  Files        9073     9098      +25     
  Lines       80086    80225     +139     
==========================================
+ Hits        39582    39668      +86     
- Misses      40504    40557      +53     

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