Starterkit operations

[AshishThakur]

• Provide ability to list installed repos.
• Add a repo
• ~Delete a repo~
• ~Sync(In case the upstream repo is changed, provide an ability to sync).~

[AshishThakur]

@AshishThakur to groom the story.

[vs4vijay]

Updated API Specs:

1. vega repo add <name> <url> will add given url's starterkits to $VEGA_HOME.

   • It supports local file path as well
   • add operation will only get successful when the given URL/Path has starterkits/ folder i.e. it should be a valid vega repository.

2. vega repo list will list all the repositories added to local machine

3. vega create --starterkit <name> --repo vs4vijay will take an optional flag for repo.

   • If repo flag is not provided, then default is considered.