Added example script that prints out metainfo metrics.

Changelog: Added

examples/metainfo/metainfo_metrics.py

+from nomad.metainfo import Section, Property, Quantity, Package
+from nomad.cli.dev import _all_metainfo_packages
+
+all_sections = 0
+all_properties = 0
+all_quantities = 0
+sections = dict()
+properties = dict()
+quantities = dict()
+definitions = set()
+metainfo = _all_metainfo_packages()
+
+for definition, _, _ in metainfo.m_traverse():
+    if definition in definitions:
+        continue
+    definitions.add(definition)
+
+    package = definition
+    while package and not isinstance(package, Package):
+        package = package.m_parent
+    if package is None:
+        continue
+
+    if isinstance(definition, Section):
+        all_sections += 1
+        sections[package] = sections.get(package, 0) + 1
+    if isinstance(definition, Property):
+        all_properties += 1
+        properties[package] = properties.get(package, 0) + 1
+    if isinstance(definition, Quantity):
+        all_quantities += 1
+        quantities[package] = quantities.get(package, 0) + 1
+
+
+for package in sections.keys():
+    print(f'{package.name}: {sections[package]}, {properties.get(package, 0)}, {quantities.get(package, 0)}')
+
+print(f'SUM: {all_sections}, {all_properties}, {all_quantities}')