Add job inheritance and start refactoring

This begins a lot of related changes refactoring config loading,
the data model, etc., which will continue in subsequent changes.

Change-Id: I2ca52a079a837555c1f668e29d5a2fe0a80c1af5
diff --git a/tests/fixtures/config/in-repo/common.yaml b/tests/fixtures/config/in-repo/common.yaml
index 96aebd6..f38406b 100644
--- a/tests/fixtures/config/in-repo/common.yaml
+++ b/tests/fixtures/config/in-repo/common.yaml
@@ -1,6 +1,6 @@
 pipelines:
   - name: check
-    manager: IndependentPipelineManager
+    manager: independent
     source:
       gerrit
     trigger:
@@ -14,7 +14,7 @@
         verified: -1
 
   - name: tenant-one-gate
-    manager: DependentPipelineManager
+    manager: dependent
     success-message: Build succeeded (tenant-one-gate).
     source:
       gerrit
diff --git a/tests/fixtures/config/in-repo/zuul.conf b/tests/fixtures/config/in-repo/zuul.conf
index 14708aa..1910084 100644
--- a/tests/fixtures/config/in-repo/zuul.conf
+++ b/tests/fixtures/config/in-repo/zuul.conf
@@ -2,7 +2,7 @@
 server=127.0.0.1
 
 [zuul]
-tenant_config=tests/fixtures/config/in-repo/main.yaml
+tenant_config=config/in-repo/main.yaml
 url_pattern=http://logs.example.com/{change.number}/{change.patchset}/{pipeline.name}/{job.name}/{build.number}
 job_name_in_report=true