fix(cluster-scanner): Fix generate kubeconfig script to be able handle context name with special characters

[maratsal]

What this PR does / why we need it:

Fix generate_kubeconfig.sh script to be able handle context name with special characters, so that context name like arn:aws:eks:us-east-2:XXXXXXXXX:cluster/eks-i044e3wc would not cause problems on running script. All : and / will be replace by -

Checklist

• Title of the PR starts with type and scope, (e.g. feat(agent,node-analyzer,sysdig-deploy):)
• Chart Version bumped for the respective charts
• Variables are documented in the README.md (or README.tpl in some charts)
• Check GithubAction checks (like lint) to avoid merge-check stoppers
• All test files are added in the tests folder of their respective chart and have a "_test" suffix