Add currency UoM configuration to runtime.cfg (#1808)

Signed-off-by: Florian Hotze <dev@florianhotze.com>

Author: florian-h05

distributions/openhab/src/main/resources/conf/services/runtime.cfg

@@ -37,6 +37,20 @@
 #org.openhab.persistence:default=
 
 
+##################################### UNIT #####################################
+
+# The service that is used to provide a set of currencies and their exchange rates.
+# Available options include:
+#   - org.openhab.core.internal.library.unit.FixedCurrencyProvider
+#   - org.openhab.core.internal.library.unit.LocaleBasedCurrencyProvider
+#
+#org.openhab.units:currencyProvider=
+
+# The base currency of this system when the fixed currency provider is used, e.g. EUR.
+#
+#org.openhab.units:fixedBaseCurrency=
+
+
 #################################### AUDIO #####################################
 
 # This parameter defines the default audio source to use (if not set, the first available one will be used.