Merge pull request #32 from diutsu/develop

[Expenditure] Bug fix: makes file a required field on the addFile schema
[Missions] Refactor: Finished the MissionsState refactor; remove
redundant code, and made the dependencies between states more obvious.
Updated dependency of workflow to v1.1.1
[maven-release-plugin] prepare release v1.3.0
Merge branch 'release/1.3.0' into develop
[maven-release-plugin] prepare for next development iteration
Integraded external-accounting-integration. Fixes: https://github.com/ist-dsi/dot/issues/10
[Missions] Refactor missionItem/*VehiclItem.jsp, removes unused files,
schemas are being used being used instead.
closes #4