Sitefinity 15.1 Support

[nathaniel-chadwick]

Is your feature request related to a problem? Please describe.
Currently, the migration tool supports 14.4, the current LTS for Sitefinity. Sitefinity has released 15.1 and we should see how the migration tool runs with a 15.1 project. Will require a nuget package update and could require changes to the EF context/models and the static Sitefinity types definitions.

Describe the solution you'd like
A separate Migration.Toolkit.Sitefinity.Data project specific to 15.1 that will allow the end user to reference from the Migration.Toolkit.Sitefinity project

Describe alternatives you've considered
N/A

Additional context
Sitefinity will also be releasing a 15 LTS at some time but there is no scheduled release date at this time.