Support parallelism

[aripalo]

Tools such as Terraform (via parallelism=n – which defaults to 10) can invoke the vegas-credentials credential process concurrently, leading into problematic situations where multiple vegas-credentials processes are and/or:

1. prompting the user for MFA
2. accessing the filesystem cache which results into error as:

   Badger obtains a lock on the directories so multiple processes cannot open the same database at the same time

To circumvent this, we use alexflint/go-filemutex to assign a lock to a specific lock-control directory at the beginning of the command and unlocking the directly once the main command (getCredentials function) has been executed.

[sonarqubecloud]

SonarCloud Quality Gate failed.   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

0.0% Coverage
0.0% Duplication

[aripalo]

Quality gate issues will be fixed later with a refactor prepping for v1 release.