Feature: #17309 - Access flexform value via TS

See Issue #17309

Description

It is now possible to access properties of a flexform field by using TypoScript.

lib.flexformContent = CONTENT
lib.flexformContent {
    table = tt_content
    select {
        pidInList = this
    }

    renderObj = COA
    renderObj {
        10 = TEXT
        10 {
            data = flexform: pi_flexform:settings.categories
        }
    }
}

The key flexform is followed by the field which holds the flexform data and the name of the property whose content should be retrieved.