Add ability to specify Buildstream branch (non master) in benchmarking via gitlab ci variable
Description
Currently unable to specify Buildstream branch to benchmark in CI that easily. This adds the ability to parse CI variables to generate a configuration that facilitates this.
Changes proposed in this merge request:
- Add parsing of suitable CI variables.
- Add generation of bespoke configuration.
- Add whatever fixes are required to make it happen.
This merge request, when merged, will address issue/bug:
No ability to run ci on developer branches, required for bot.