Moved db.password from config file to environment variable setting

src/main/resources/application-test.properties

-spring.config.import=classpath:secret.properties
 
 spring.data.mongodb.uri=mongodb+srv://admin:${db.password}@inventory-promotions.d4nfz.mongodb\
   .net/${spring.data.mongodb.database}?retryWrites=true&w=majority

src/main/resources/application.properties

-spring.config.import=classpath:secret.properties
 
 server.port=8080
 spring.data.mongodb.uri=mongodb+srv://admin:${db.password}@inventory-promotions.d4nfz.mongodb\

src/test/resources/application-test.properties

-spring.config.import=classpath:secret.properties
 
 server.port=8080
 spring.data.mongodb.uri=mongodb+srv://admin:${db.password}@inventory-promotions.d4nfz.mongodb\