Double select device ID when create module for edge device in treeview

[czgtest]

step:
1.create new edge device
2.right-click the edge device and select "create module" menu
Actually:
it will let user to double select device ID for creating module
Except:
let user to enter module ID to create module

[formulahendry]

Remove the context menu from 'Device', only show 'create module' in 'Modules'

Please test it: https://github.com/Microsoft/vscode-azure-iot-toolkit/releases/download/v2.6.0-rc2/azure-iot-toolkit-2.6.0-rc2.vsix