WIP: Allow creating per bundle/ per group roles

[amitaibu]

#208

[amitaibu]

@pfrenssen this is just a beggining, but maybe can already give you a hint on my direction

[amitaibu]

@pfrenssen I guess it is a bit ugly having to pass either bundle ID or group ID. Which made me thing that maybe we should have two Og Roles bundles: per_bundle and per_group so the schema will just have those two keys: group_type and reference_id (bad name) . reference_id will be populated either with the bundle ID or the group ID.

[pfrenssen]

OgRole is a config entity, I don't think this supports bundles. If you look at the inherited method OgRole::bundle() you see it returns the entity type instead of the bundle. Only content entities support custom bundles out of the box.

But I actually think we can hack in bundle support easily. We just need to ensure that the bundle is stored along with the entity, that we have a $this->bundle property that we populate in the constructor, and then we can use it to handle per_bundle and per_group specific logic.

[amitaibu]

Here are some thoughts:

1. Have two classes OgRolePerBundle (= the current OgRole) and OgRolePerGroup
2. As proposed here change the schema, so we have target_id instead of bundle
3. Rename role_type to required, and make it a boolean.
4. OgRolePerBundle is now a Config entity which allows it to being exported. However it would make more sense to make OgRolePerGroup a Content entity, as it is non-exportable, and their could be thousands instances of it.

@pfrenssen what do you think about 4? Not sure how to tackle it, and still be able to share code between the classes.

[pfrenssen]

Assigning to me so I won't forget to review this and answer the questions.

[amitaibu]

A possible solution to having to reference both Config and Content is simply to have two different references fields on OgMembership.

So OgMembership::getRoles() will be responsible on looking at the right field according to the group's settings.

This means we can break it to smaller PRs:

1. Change the schema to be $entity_type_id and $identifier instead of the $entity_type/$bundle/$group_id
2. Add the OgRolePerGroup and a matching reference (base) field on OgMembership
3. Bake the logic into OgMembership::getRoles() and family