Unclear max length of an ecosystem testimonial and other feedback

[vivienlacourba]

The tooltip indicates "Shorter version of the quote that can be used in a testimonial carousel. (In that context, quote have a character limit of 180 to comfortably fit in a small screen)."

But trying to save an existing testimonial with a longer text yields a error should 2 different max length validation messages (or for 180 chars max the other for 720 chars max).

Looking at the W3C specification document neither of these limits seem define. Discussing with @koalie 180 chars definitely seems too short, and @jean-gui's test shows that 720 might already be too much for the current carousel. So a max length of 500 chars would seem better suited.

Some other issues:

• There does not seem to be a need to associate an ecosystem testimonial to multiple ecosystems.
• The default slug should take the testimonial into account i.e. "{ecosystem-shortname}-{author-name}" so "publishing-john-doe"
• The "Author Organization" (here "DAISY Consortium") is not show on the carousel, and used only as an alt tag for the logo if one was uploaded. There should be a field hint to indicate that this info will be used as the image alt text.
• Visually it seems that the logo should be centered within the white rectangle used as background.
• We might want to revisit the strategy for handling testimonials in other languages, so instead of having testimonials in any language we would only have testimonials in the language of the page (so English, Chinese or Japanese depending on which site we are).

[vivienlacourba]

Setting it as low priority for now as @koalie is still reviewing ecosystem pages with our Strategy team.