Exposing the transaction used in class Database.

[kbilsted]

This enables to do queries not supported by rainbow within the same transaction

Closes#1944

[kbilsted]

The build pipeline is failing on installing dependencies so it cannot run the tests

[kbilsted]

still errors in the pipeline. please help

Packages requiring reboot:
- vcredist140 (exit code 3010)
The recent package changes indicate a reboot is necessary.
Please reboot at your earliest convenience.
Command exited with code 3010```

[mgravell]

property please - i.e. add {get;}

[kbilsted]

done

[mgravell]

gotta love CI servers :/ working on it: #2042

[mgravell]

CI issue fixed