Remove image customization in restapi

[cekk]

Use plone.restapi new features for image scales

[mamico]

direi che però il merge di questo deve aspettare la chiusura di https://github.com/RedTurtle/design-comuni-plone-theme/pull/382 e https://github.com/RedTurtle/design-comuni-plone-theme/pull/325

[coveralls]

Pull Request Test Coverage Report for Build 8376318833

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 5 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.7%) to 63.542%

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Files with Coverage Reduction	New Missed Lines	%
src/redturtle/volto/restapi/serializer/summary.py	5	83.33%
<!--	Total:	5		-->

Totals
Change from base Build 8339947770:	-0.7%
Covered Lines:	861
Relevant Lines:	1355

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💛 - Coveralls