remove UnpackDevTask

[rymsha]

What it does: It extracts dev folder from lib-admin-ui and lib-contentstudio into ".xp" folder. dev folder contains js and d.ts files , so applications that depend on lib can use contents of dev folder in webpack for instance. (need clarification, why @alansemenov )

Users of such libs write in gradle file

npmInstall.mustRunAfter unpackDevResources

and after that

task webpack {
...
inputs.dir ".xp/dev"

and after that (often forgotten), to exclude dev folder from final application

project.afterEvaluate {
    jar {
        bnd ('Private-Package': '!dev.*, *;-split-package:=merge-first')
    }
}

A few problems:

• OSGI removing dev.* package actually may exclude some important dependencies in future ( because right now it is not that easy to find a good example, but with new top level domain .dev it is just a matter of time)
• it is a niche feature with very surprising behavior. Feels like a wrong tool for some simple task.
• It is error prone (easy to forget that dev must be excluded, some problems can only be solved with deletion of .xp folder, etc...)
• it is still quite verbose: not enough to "just" call the task. One should know how to use outputs properly