Change Status.Order to Status.Position, and the ByStatusOrder type to
ByStatusPosition to make it clearer that status' are ordered by their
position on the Kanban board.
Create a new Board type in the board package which is a wrapper around
the BoltDB db pointer to remove direct access to the BoltDB database
from the UI package.
Create a BoltItem interface which is used to make
the database fucntions more generic.
As part of this change, the Status and Card types
have migrated back into the board package.
- Introduced internal packages for different components of the kanban
board.
- Simplified and refactored the database tests based on linting feedback.
- Add tests for the board package.
