Access parent's application.properties from dependent project in spring boot

I am developing a multi-module project in Spring Boot where the project structure is as follows:

com.app.parent  <- parent pom with version numbers and common dependencies (POM)
com.app.core    <- repository and service layer, models, DTOs (JAR)
com.app.rest    <- rest API (WAR)
com.app.soap    <- soap API (WAR)

The pom.xml file for the parent project is:

<artifactId>app-parent</artifactId>
<packaging>pom</packaging>
<name>app-parent</name>

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.3.RELEASE</version>
    <relativePath/>
</parent>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

The pom.xml file for the core project is:

<artifactId>app-core</artifactId>
<packaging>jar</packaging>
<name>app-core</name>

<parent>
    <groupId>com.app</groupId>
    <artifactId>app-parent</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <relativePath>../app-parent/pom.xml</relativePath>
</parent>

<dependencies>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
</dependencies>

The pom.xml for the rest project is:

<artifactId>app-rest</artifactId>
<packaging>war</packaging>
<name>app-rest</name>

<parent>
    <groupId>com.app</groupId>
    <artifactId>app-parent</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <relativePath>../app-parent/pom.xml</relativePath>
</parent>

<dependencies>
    <dependency>
        <groupId>com.app</groupId>
        <artifactId>app-core</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
</dependencies>

The entry point for the app-core project is:

@SpringBootApplication
public class CoreApplication {

    public static void main(String[] args) {
        SpringApplication.run(CoreApplication.class, args);
    }
}

The entry point for the app-rest project looks exactly the same.

I have created an application.properties file within core/src/main/resources/ which contains database config etc. and I can compile/test the app-core project just fine. However, when I try to run or test the app-rest project I get errors related to the absence of application.properties file

Cannot determine embedded database driver class for database type NONE. If you want an embedded database please put a supported one on the classpath.

How do I get the child project to load the parent's application.properties file? Do I have to create a symlink to the parent file, or do I expressly load the parent's property file via @PropertySource? What do others do in this scenario?