Service manager v4

[ramchale]

This still needs a lot of tidy up, but seems fairly close to a working version with service-manager v4.

Raised as a draft to check if there's anything else obvious I'm missing, and seek some help fixing the remaining tests.

(The block of commented out code in Factory being an obvious area that needs a look)

[gsteel]

Just playing around locally with this patch - and validator ^3.6 will defo be needed so that we can $validators->build(ValidatorChain::class, $spec).

I think we might need to do some more cleanup before we can figure out what's tripping up those tests… 🤔

[ramchale]

Thanks for the work on resolve the underlying changes @gsteel

I've just done a quick rebase and fixed a few obvious bits. Busy day ahead, so I'll get back to this when I can. Happy for anyone else to make progress with it in the meantime if they'd like to

[gsteel]

Cheers @ramchale 👍

[ramchale]

This fails with "ServiceNotFoundException: Unable to resolve service "foo_validator" to a factory"

Debugging thorugh, it looks like the filter also can't be resolved but does not throw an Exception.
The build methods of the filterPluginManager and validatorPluginManager don't seem like they try to use the 'services', so I'm not sure this can pass unless we want to make further changes to those.

Worth double checking though, as I'm much less familiar with the internals of the plugin managers than some other parts of the code