EZP-30636: Provided forward compatibility for eZ Platform Extension

[alongosz]

Question	Answer
JIRA issue	EZP-30636
Bug/Improvement	no
New feature	yes
Target version	1.0 for eZ Platform v2.5.x LTS and 3.0@beta2
BC breaks	yes
Tests pass	yes
Doc needed	yes

This PR provides forward compatibility with eZ Platform 3.0 by means of eZ Platform Core Bundle and its Extension, so the Developers and Maintainers are able to prefix their eZ Platform configuration with

ezplatform:

instead of

ezpublish:

Current implementation simply prepends ezplatform configuration to ezpublish extension. This by no means is a complete solution. It's rather a workaround to simplify migration.

For eZ Platform 3.0 we plan to provide fully functional EzPlatformCoreBundle which registers ezplatform extension and replaces EzPublishCoreBundle and ezpublish extension.

I still believe this is a good way to go, even if it is a workaround. I took into the account suggestions from the internal Sprint Demo and targeted it for eZ Platform 2.5.x LTS so that PR provides more significant value.

Open question

• Should we drop "Core" from the Bundle and Extension name? So it's just EzPlatformBundle and EzPlatformExtension? // Internal Sync: No.

Doc

To use ezplatform instead of ezpublish in their 2.5.x ezplatform.yml configuration files, the Developers must enable the EzSystems\EzPlatformCoreBundle\EzPlatformCoreBundle in their Kernel.

v2.5

app/AppKernel.php:

        $bundles = [
            // ...
            new EzSystems\EzPlatformCoreBundle\EzPlatformCoreBundle(),
            // ...
        ];

v3.0

config/bundles.php:

return [
    // ...
    EzSystems\EzPlatformCoreBundle\EzPlatformCoreBundle::class => ['all' => true],
    // ...
];

QA

• Test configuration of ezplatform extension (replacing ezpublish with ezplatform in ezplatform.yml (you could use the alongosz:ezp-30636-ezplatform-extension branch),
• Perform sanity checks for the current ezpublish configuration.

TODO

• Rebase after merging [Travis] Added code style checking job #10
• Create Bundle.
• Create Extension.
• Prepend ezpublish extension with config from ezplatform extension.
• Double check if everything is working as expected.

[mnocon]

Looks ok to me, on v2 with ezplatform and ezpublish config prefixes and on v3 with ezplatform one.