Make the build of the sample composite

[stephanenicolas]

@kshirsagarps

The build of sample would look like:

[build lib]<--[deploy to local repo]-->[save version to file] 

[lib:deploy to local repo]<--[load version from file]<--[build sample]

https://docs.gradle.org/current/userguide/composite_builds.html

Then on CI, we will just build the sample app and it should build everything.