Run maven in offline mode when resolving variables in quickstart bootstrap scripts

[drewfarris]

This update forces maven to run in offline mode when resolving environment variables for the bootstrap scripts in the quickstart.

Aside from being a good citizen and not hitting maven central, when running in the context of the quickstart container, the maven executions used to populate environment variables in the bootstrap scripts are incredibly slow...

[root@74633f45d549 datawave-quickstart]# time mvn -q -f ${DW_CLOUD_HOME}/docker/pom.xml help:evaluate -DforceStdout -Dexpression=sha512.checksum.wildfly
fcbdff4bc275f478c3bf5f665a83e62468a920e58fcddeaa2710272dd0f1ce3154cdc371d5011763a6be24ae1a5e0bca0218cceea63543edb4b5cf22de60b485
real    0m34.699s
user    0m7.059s
sys     0m0.384s
[root@74633f45d549 datawave-quickstart]# time mvn -o -q -f ${DW_CLOUD_HOME}/docker/pom.xml help:evaluate -DforceStdout -Dexpression=sha512.checksum.wildfly
fcbdff4bc275f478c3bf5f665a83e62468a920e58fcddeaa2710272dd0f1ce3154cdc371d5011763a6be24ae1a5e0bca0218cceea63543edb4b5cf22de60b485
real    0m2.131s
user    0m5.634s
sys     0m0.342s

There's a delay when downloading group level plugin metadata. It is unlikely necssary to do this when resolving a property in a pom to a value.

Downloading from central: https://repo.maven.apache.org/maven2/org/apache/xmlbeans/maven-metadata.xml
Downloading from central: https://repo.maven.apache.org/maven2/com/diffplug/spotless/maven-metadata.xml
Downloading from central: https://repo.maven.apache.org/maven2/gov/nsa/datawave/plugins/maven-metadata.xml
[WARNING] Could not transfer metadata gov.nsa.datawave.plugins/maven-metadata.xml from/to central (https://repo.maven.apache.org/maven2): status code: 429, reason phrase: Too Many Requests (429)
[WARNING] Could not transfer metadata com.diffplug.spotless/maven-metadata.xml from/to central (https://repo.maven.apache.org/maven2): status code: 429, reason phrase: Too Many Requests (429)
[WARNING] Could not transfer metadata org.apache.xmlbeans/maven-metadata.xml from/to central (https://repo.maven.apache.org/maven2): status code: 429, reason phrase: Too Many Requests (429)