Previously, an item could only have a 'deprecated' boolean flag to
indicate that the property is deprecated. It is desirable to provide an
additional description for the deprecation as well as the name of the
property to use instead.
The `deprecated` boolean flag is now supported. Instead, a `deprecated`
object can be specified with two optional attributes: `reason` to provide
an explanation for the deprecation and `replacement` to refer to the
property that should be used instead. If none of them is present, an
empty deprecation object should be set.
For backward compatibility, the `deprecated` field is still set.
Deprecation information can only set via manual meta-data.
Closes gh-3449
Add a new `spring-boot-configuration-metadata` module that provides an
API to manipulate Spring Boot configuration meta-data. Can read meta-data
from arbitrary locations, though the standard
`META-INF/spring-configuration-metadata.json` location must be preferred.
Closes gh-1970
Add a companion module that IDE developers can use to read configuration
metadata from multiple sources into a single repository.
ConfigurationMetadataRepository provides access to groups and items as
well as an harmonized view on "sources" (that is the POJOs that have
contributed to a given group).
Closes gh-1970
