Spin up service containers when using host executor

[chibidev]

Act version

act version 0.2.74

Feature description

Currently, service containers defined for the workflow seem to be only evaluated and brought up when the workflow is executed within the runner container. Specifying -P xyz=-self-hosted removes this convenience and requires additional measures to create the same execution context.

Since changing this behavior might end-up breaking current scripts, I'm thinking whether adding a new command line switch (e.g. --with-services, although I'm pretty sure someone far smarter than me can come up with a better name) to opt-into this convenience would be something the current maintainers might consider.

Happy to contribute myself, if the approach seems reasonable, I just wanted to test the waters first.