Track new metrics using backbox exporter

[Rajendraladkat1919]

few metrics I am thinking of as part of this exporter as

1. Overall time taken by commit from commit to first successful build.
2. avg. time taken by each commit to build on CI server.
3. waiting/queuing time of each commit on the CI system.
4. How many times a commit failed before a successful merge into main/master?
5. How many times does the master branch run in a day on CI server?
6. Total number of build in days from master as well as PR branch of each commit.
7. Total successful or failed build for single commit until successful deployment.