Merge pull request #29 from EricpolUkraine/development

Development
BTM\VisasAndPermits test was fixed.
Merge pull request #509 from nazariitashak/development

BTM\VisasAndPermits test was fixed.
To issue #493
Merge pull request #510 from AnnaStorozhenko/development

To issue #493
Merge pull request #511 from Bohdan-Tereta/development

Unit tests for Messenger and integration tests for ACC are fixed
Merge pull request #512 from Bohdan-Tereta/development

Added Holiday Migration, Reverted InitialCreate migration
Merge pull request #513 from EricpolUkraine/development

Pre-release merge from 'development' to 'test' v1.15.4-alpha
Merge pull request #516 from EricpolUkraine/test

Release merge v1.15.4.0
Fixed three unit tests dependent on current date