Change mutex to counting semaphore

The mutex in zuul is great but is limited to run one job at the same
time. Some use cases like using a limited number floating licenses in
jobs cannot be handled with this. Thus this changes the mutex
functionality to a counting semaphore (which defaults to 1).

This is a port of Ida589e49bc6694f4ccc4c586e0d43b391b8c3ae4 to zuulv3
branch.

Change-Id: Icf4013a6215e2b10ca8e6309928b9e5881dda02c
diff --git a/tests/fixtures/config/multi-tenant-semaphore/git/common-config/zuul.yaml b/tests/fixtures/config/multi-tenant-semaphore/git/common-config/zuul.yaml
new file mode 100644
index 0000000..d18ed46
--- /dev/null
+++ b/tests/fixtures/config/multi-tenant-semaphore/git/common-config/zuul.yaml
@@ -0,0 +1,13 @@
+- pipeline:
+    name: check
+    manager: independent
+    source: gerrit
+    trigger:
+      gerrit:
+        - event: patchset-created
+    success:
+      gerrit:
+        verified: 1
+    failure:
+      gerrit:
+        verified: -1
diff --git a/tests/fixtures/config/multi-tenant-semaphore/git/org_project1/README b/tests/fixtures/config/multi-tenant-semaphore/git/org_project1/README
new file mode 100644
index 0000000..9daeafb
--- /dev/null
+++ b/tests/fixtures/config/multi-tenant-semaphore/git/org_project1/README
@@ -0,0 +1 @@
+test
diff --git a/tests/fixtures/config/multi-tenant-semaphore/git/org_project2/README b/tests/fixtures/config/multi-tenant-semaphore/git/org_project2/README
new file mode 100644
index 0000000..9daeafb
--- /dev/null
+++ b/tests/fixtures/config/multi-tenant-semaphore/git/org_project2/README
@@ -0,0 +1 @@
+test
diff --git a/tests/fixtures/config/multi-tenant-semaphore/git/tenant-one-config/playbooks/project1-test1.yaml b/tests/fixtures/config/multi-tenant-semaphore/git/tenant-one-config/playbooks/project1-test1.yaml
new file mode 100644
index 0000000..f679dce
--- /dev/null
+++ b/tests/fixtures/config/multi-tenant-semaphore/git/tenant-one-config/playbooks/project1-test1.yaml
@@ -0,0 +1,2 @@
+- hosts: all
+  tasks: []
diff --git a/tests/fixtures/config/multi-tenant-semaphore/git/tenant-one-config/zuul.yaml b/tests/fixtures/config/multi-tenant-semaphore/git/tenant-one-config/zuul.yaml
new file mode 100644
index 0000000..5e377e7
--- /dev/null
+++ b/tests/fixtures/config/multi-tenant-semaphore/git/tenant-one-config/zuul.yaml
@@ -0,0 +1,13 @@
+- job:
+    name: project1-test1
+    semaphore: test-semaphore
+
+- project:
+    name: org/project1
+    check:
+      jobs:
+        - project1-test1
+
+- semaphore:
+    name: test-semaphore
+    max: 1
diff --git a/tests/fixtures/config/multi-tenant-semaphore/git/tenant-two-config/playbooks/project2-test1.yaml b/tests/fixtures/config/multi-tenant-semaphore/git/tenant-two-config/playbooks/project2-test1.yaml
new file mode 100644
index 0000000..f679dce
--- /dev/null
+++ b/tests/fixtures/config/multi-tenant-semaphore/git/tenant-two-config/playbooks/project2-test1.yaml
@@ -0,0 +1,2 @@
+- hosts: all
+  tasks: []
diff --git a/tests/fixtures/config/multi-tenant-semaphore/git/tenant-two-config/zuul.yaml b/tests/fixtures/config/multi-tenant-semaphore/git/tenant-two-config/zuul.yaml
new file mode 100644
index 0000000..a310532
--- /dev/null
+++ b/tests/fixtures/config/multi-tenant-semaphore/git/tenant-two-config/zuul.yaml
@@ -0,0 +1,13 @@
+- job:
+    name: project2-test1
+    semaphore: test-semaphore
+
+- project:
+    name: org/project2
+    check:
+      jobs:
+        - project2-test1
+
+- semaphore:
+    name: test-semaphore
+    max: 2
diff --git a/tests/fixtures/config/multi-tenant-semaphore/main.yaml b/tests/fixtures/config/multi-tenant-semaphore/main.yaml
new file mode 100644
index 0000000..b1c47b1
--- /dev/null
+++ b/tests/fixtures/config/multi-tenant-semaphore/main.yaml
@@ -0,0 +1,15 @@
+- tenant:
+    name: tenant-one
+    source:
+      gerrit:
+        config-repos:
+          - common-config
+          - tenant-one-config
+
+- tenant:
+    name: tenant-two
+    source:
+      gerrit:
+        config-repos:
+          - common-config
+          - tenant-two-config