Install OHRM via predefined ENV vars

[samanthajayasinghe]

Is your feature request related to a problem? Please describe.
As a user, I would like to install OHRM via a pre-defined env vars on the docker container /k8 pod

Describe the solution you'd like
It's better to support CLI installer via the following ENV Vars

OHRM-DB-HOST // default to localhost 
OHRM-DB-PORT // default to 3306
OHRM-DB-USER 
OHRM-DB-PASSWORD
OHRM-DB-NAME // default to orangehrm 
OHRM-ADMIN-USER-PASSWORD

After successfully installation, I would like to get the installed version via ENV var too.

OHRM-VERSION