Add classes and prototype name in image collection element

[maximehuran]

Update collection type to have prototype name

To avoid issue with collection forms javascript

Add some classes on image collection type

In order to have display in a special segment

Also you have specific class to customize the display of it with collection--flex

For example you can add this to have flex display of your elements

.collection--flex > div {
    display: flex;
    flex-flow: wrap;
}

.collection--flex > div > div {
    margin-right: 10px;
}