Add cloud-bom

[jpenilla]

Allows for declaring cloud versions in one spot, instead of needing to repeat it for every module. Also prevents version mismatches when used.

To use add a dependency on the bom:

Gradle:

dependencies {
    implementation(platform("cloud.commandframework:cloud-bom:VERSION"))
}

Maven:

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>cloud.commandframework</groupId>
            <artifactId>cloud-bom</artifactId>
            <version>VERSION</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

and then dependencies on individual cloud modules can be declared without a version, and the version specified by the bom will be used.