Add support to auto-layout properties

[darioaschero]

Is your feature request related to a problem? Please describe. At the moment isn't possible to define a token value for the size properties which, when applied, will be interpreted as “Fill container”. Since also the others auto layout settings are not supported, they can be considered as part of this feature request.

Describe the solution you'd like Auto layout related properties can be categorised in two groups:

Size: Size tokens could support two additional values 100% ( fill container) and auto (hug content)

Layout: Figma supports a subset of the flexbox api which can be summarised as follows

flex-direction: vertical | horizontal 


align-items: center | flex-strart | flex-end

justify-content: center | flex-start | flex-end | space-between 

Considering that these properties are all enum, the first approach which came to my mind is to treat them as a small token composition and use radio buttons to assign values. If this approach worth to be explored, I can produce a mock up of the ui.

[C3PablO]

Looking forward to seeing progress on this ;)