Add file permission and ownership tests for install script

[swiatekm]

We should verify that all the files created by the install script have the right ownership and permissions. The lack of these has already caused bugs via unrelated changes. For example: #816

• System config file (test(scripts/install.sh): check config path permissions and ownership #819)
• User config file
• File storage
• Extension credentials directory

[swiatekm]

Closing in favor of SumoLogic/sumologic-otel-collector-packaging#90