[REL] v3.0.0-alpha.23

v3.0.0-alpha.22

• [IMP] tools: add support for alpha release in release script
• [IMP] playground: improve file drag & drop
• [IMP] playground: allow slashes for subfolder creation
• [IMP] playground: allow creating a subfolder
• [FIX] blockdom: fix bad handling of style property
• [FIX] playground: fix wrong import in hibou tutorial
• [DOC] playground: add a final step to the hibou os tutorial
• [IMP] playground: various improvements