Add support for Counter-Strike: Source

[Mikusch]

Related issue: #17

Adds support for Counter-Strike: Source to the plugin. The general goal of this PR is to generalize the plugin and allow more games to be supported.

To Do:

• Make sure no mod-specific files and identifiers are being referenced inside the code and configuration files
• Rebrand the plugin and rename the repository since "tf-vehicles" is no longer a fitting name
• Check if more games can be supported without having to dig for signatures