CB-11279 Support arbitrary repositories for 'coho nightly'

[vladimir-kotikov]

This PR adds the following features to coho nightly command:

• it now accepts --repo flag to specify repos to build nightlies for (instead of using predefined repos) . If --repo is not specified, cordova-cli and cordova-lib will be built.
• it now updates dependencies for every package to point to newly released nightly versions
• it handles the situation when the repo is not yet published under nightly tag gracefully

[nikhilkh]

One minor comment - LGTM otherwise