Validate the repository before starting the release process

[kasunbg]

It is a common occurrence that people only find the issues in their git repositories when they are half-way through the release process. Due to things such as blindly copying pom files, the scm configs etc. are not properly updated when creating new repos.

So, as the very first step, we need to add some validation steps. Following can be validated initially.

1. Verify whether the cloned git repo url matches with the scm config in the root pom.

2. Verify whether the project.scm.id specified is the same as the one in settings.xml of jenkins. Currently, jenkins' settings.xml has multiple server configs to support commonly used ids - my-scm-server, github-scm, git-scm-server etc.

3. No SNAPSHOT dependencies.