Switch development config to use ConfigAggregator

[kynx]

Q	A
Documentation	no
Bugfix	no
BC Break	no
New Feature	yes
RFC	no
QA	no

Description

This PR changes development.config.php.dist to use a ConfigAggregator so https://github.com/laminas/laminas-component-installer/pull/68 can inject --dev-only config providers. It also adds the ability to load dev-only configuration from {,*.}{global,local}-development.php files - like MVC does - so settings in the development config providers can be overridden.

I'm not sure what I can do to test these changes. As far as I can tell the existing tests don't cover the structure of the config files, but if anyone's got any pointers...

[Xerkus]

You might want to rebase

[kynx]

Grrr.... done.

[kynx]

Hey @Xerkus I ended up using global.dev.php.dist instead of local.dev.php.dist - I think that's better for project-wide developer settings that get checked in to VCS.