The `spring.datasource.name` property was hidden behind the 'name'
attribute of the Tomcat connection pool (since we are mapping all
datasource implementations on the `spring.datasource` namespace.
This commit replace the injected value by hand with the use of the
regular `DataSourceProperties`. That way, we generate proper meta-data
for it as well.
Closes gh-3755
d1a4d6958a