bundles: install yarn globally instead of in each individual bundle

bundles/element-web/items.py

@@ -29,9 +29,8 @@ actions = {
     'element-web_yarn': {
         'command': ' && '.join([
             'cd /opt/element-web',
-            'npm install yarn',
-            'node_modules/yarn/bin/yarn install --pure-lockfile --ignore-scripts',
-            'node_modules/yarn/bin/yarn build',
+            'yarn install --pure-lockfile --ignore-scripts',
+            'yarn build',
         ]),
         'needs': {
             'pkg_apt:nodejs',

bundles/hedgedoc/items.py

@@ -55,10 +55,9 @@ actions = {
     'hedgedoc_yarn': {
         'command': ' && '.join([
             'cd /opt/hedgedoc',
-            'npm install yarn',
-            'node_modules/yarn/bin/yarn install --production=true --pure-lockfile --ignore-scripts',
-            'node_modules/yarn/bin/yarn install --ignore-scripts',
-            'node_modules/yarn/bin/yarn build',
+            'yarn install --production=true --pure-lockfile --ignore-scripts',
+            'yarn install --ignore-scripts',
+            'yarn build',
         ]),
         'needs': {
             'file:/opt/hedgedoc/config.json',

bundles/nodejs/items.py

@@ -0,0 +1,9 @@
+actions = {
+    'nodejs_install_yarn': {
+        'command': 'npm install -g yarn@latest',
+        'unless': 'test -e /usr/lib/node_modules/yarn',
+        'needs': {
+            'pkg_apt:nodejs',
+        },
+    },
+}

bundles/nodejs/metadata.py

@@ -3,6 +3,7 @@ defaults = {
         'additional_update_commands': {
             # update npm to latest version
             'npm install -g npm@latest',
+            'npm install -g yarn@latest',
         },
         'repos': {
             'node': {

bundles/powerdnsadmin/items.py

@@ -59,8 +59,7 @@ actions = {
         'triggered': True,
         'command': ' && '.join([
             'cd /opt/powerdnsadmin/src',
-            'npm install yarn',
-            'node_modules/yarn/bin/yarn install --pure-lockfile --ignore-scripts',
+            'yarn install --pure-lockfile --ignore-scripts',
             'FLASK_APP=/opt/powerdnsadmin/src/powerdnsadmin/__init__.py /opt/powerdnsadmin/venv/bin/flask assets build',
             'chown -R powerdnsadmin:powerdnsadmin /opt/powerdnsadmin/src/powerdnsadmin/static/',
         ]),