v.6.19.4

Improvements:

1. [LUNA-6482] The task scheduling was added for Clusterization and Export objects tasks. See scheduling for details.

2. [LUNA-6520] The task scheduling was added for Estimator task. See scheduling for details.

Bugs fixed:

1. [LUNA-6518] Fixed description for body matching and face matching

2. [LUNA-6533] Internal server error was fixed when requesting get features with perpetual license

Migration:

See a migration manual.

[LUNA-6533] See a migration manual.