Improve "local configuration" topic in deployment section
Description of the bug or enhancement
Example of a person confused with local configuration: https://www.cuba-platform.com/discuss/t/deployment-with-configuration-out-of-war/10059
Deployment section: http://cubadev:8181/manual/deployment.html
It does not clearly describe the concept of local configuration which can be applied to the system at deployment time, and does not specify place for local.app.properties.
related to #501
the same: https://www.cuba-platform.com/discuss/t/change-dbms-type-via-local-app-properties/10237
also answer questions asked in these topics: https://www.cuba-platform.ru/discuss/t/peremennye-okruzheniya/3907/4 (environment-specific properties)
https://www.cuba-platform.ru/discuss/t/razvyortyvanie-dvuh-kopij-prilozheniya-na-odnom-servere/3911/3 (two webapp copies in one tomcat)
https://www.cuba-platform.ru/discuss/t/ukazyvat-nastrojki-podklyucheniya-k-hranilishham-dannyh-vo-vremya-zapuska-prilozheniya/3914/2 (change database settings on prod server)