Adding one more parameter project name to the snapcraft init command

[XiaoGuo, Liu]

So far, snapcraft init works well in most of the cases. However, it would be best to have the following kind of format:

$ snapcraft init project_name

so that, the template is like:

====================================================
name: project_name # you probably want to 'snapcraft register <name>'
version: '0.1' # just for humans, typically '1.2+git' or '1.3.2'
summary: This is balabal project_name
description: |
  This is a template project for project_name

grade: devel # must be 'stable' to release into candidate/stable channels
confinement: devmode # use 'strict' once you have the right plugs and slots

parts:
  my-part:
    # See 'snapcraft plugins'
    plugin: nil
===================================================

A developer does not need to change the template much to start to work on the new project straight away.

Now, every time, I have to change the strings in the template thought it is not a big effort.

Thanks & best regards,
XiaoGuo