Implement importing and exporting of layout files

[PathogenDavid]

Related to #1956

[glopesdev]

@bruno-f-cruz @PathogenDavid do we still want this given we are now going in the direction where the layout file is simply a local workflow editor setting? We can discuss this during the next DCM but I feel we should investigate whether resolving #2137 might render this issue obsolete.

[bruno-f-cruz]

Given the use case I had in mind I think that #2137 would be my preference. However since it is a decision that may influence future changes in the language this could still be a valuable alternative to consider.

[PathogenDavid]

Tbh I kinda dislike #2137 as the solution to this problem, but I also don't have a horse in this race. If nobody in DCM wants to advocate for this solution I'm OK with waiting to see if people complain that they don't like that approach as a replacement for layout files.