Export / Import Buttons (Sharing Data within QeApp)

[AndresOrtegaGuerrero]

These buttons can be use to allow sharing QeAppWorkChain between users.
The button of export should do "verdi archive create my-qeapp-calculation.aiida --nodes pk"
The button of import should "verdi archive create my-qeapp-calculation.aiida"

The import should guarantee to display the results and not generate a conflict with the plugins that the different users might have.