Rename configuration parameter prefix from `dbadmin` to `snapadmin`

[aileftech]

The configuration properties prefix will change to 'snapadmin' with the next release (0.2.0). From:

## The first-level part of the URL path: http://localhost:8080/${baseUrl}/
dbadmin.baseUrl=admin

## The package(s) that contain your @Entity classes
## accepts multiple comma separated values
dbadmin.modelsPackage=your.models.package,your.second.models.package

to

## The first-level part of the URL path: http://localhost:8080/${baseUrl}/
snapadmin.baseUrl=admin

## The package(s) that contain your @Entity classes
## accepts multiple comma separated values
snapadmin.modelsPackage=your.models.package,your.second.models.package