Run plugins in contained runners (containers)

[mostafa]

The go-plugin v1.5.0 introduced a new feature, called Runner, that allows custom command runner implementations, that are mutually exclusive with Cmd and Reattach. Based on the example module added to the go-secure-stdlib, a plugin container can be constructed that runs the plugins inside an OCI container, which effectively isolates the plugins and allows more restrictions/limitations to be applied to those plugins.

The idea is to integrate this in GatewayD to achieve plugin isolation in containers, and be able to control plugins from a separate runner.