Improve offline player handling

[citRaTTV]

Describe Pull request Leverages built-in QBCore offline player handling for management of employees / gang members. General cleanup.

If your PR is to fix an issue mention that issue here

Questions (please complete the following information):

• Have you personally loaded this code into an updated qbcore project and checked all it's functionality? yes
• Does your code fit the style guidelines? yes
• Does your PR fit the contribution guidelines? yes