Add file permission and ownership tests for install script

[swiatekm]

Moving SumoLogic/sumologic-otel-collector#817 here.

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 sumologic-otel-collector#819)
• User config file
• File storage
• Extension credentials directory