Fixed various i18n inline python usage and updated python i18n strings (

datacommonsorg#4946)

* Updated pybabel mapping configuration to include `shared_api/place.py`
and `lib/i18n_messages.py`
* Updated `i18n_messages.py` to include calls to `gettext` & translation
descriptions so pybabel can automatically extract them.
* Reverted `translate` calls back to `gettext` because the
[pybabel](https://github.com/datacommonsorg/website/blob/master/scripts/extract_messages.sh#L36)
extraction tool wasn't able to properly pull the messages from the
python code.
* Fixed {% trans %} calls in `server/templates/metadata/labels.html`

server/babel-mapping.ini

@@ -1,5 +1,6 @@
-[python: **/api/place.py]
+[python: **/shared_api/place.py]
+[python: **/lib/i18n_messages.py]
 [jinja2: **/templates/**.html]
 encoding = utf-8
-extensions=jinja2.ext.i18n,jinja2.ext.autoescape,jinja2.ext.with_
-ext.i18n.trimmed=True
+extensions=jinja2.ext.i18n
+ext.i18n.trimmed=True

server/config/chart_config/crime_new.json

@@ -408,7 +408,7 @@
     "category": "Crime",
     "title_id": "CHART_TITLE-Violent_crime",
     "title": "Violent crime",
-    "description": "Total number of violent incidents",
+    "description": "Total number of violent crime incidents",
     "variables": [
       "Count_CriminalActivities_ViolentCrime"
     ],