Re-order the preference for cyclonedx maven plugin

[prabhu]

Currently, cdxgen uses the cyclonedx maven plugin and then tries the maven dependency:tree command as a fallback. Changing the order to use the maven command first might help cdxgen a bit:

• Better re-construct per module and per project dependency tree. Currently, it gets merged into a single tree.
• Better deal with private packages where only a single project or module needs the required auth (so could be skipped).
• Go a bit faster

[prabhu]

With the latest master, there is an option to use maven dependency tree plug-in instead of the cyclonedx plug-in. In my test, I found the dependency tree to be slightly better in this mode without any pseudo pom type components. Attributes such as description, publisher, external references, and hashes are currently missing though, so best to use the default settings in cdxgen, if those attributes are important for your needs.

export PREFER_MAVEN_DEPS_TREE=true

Removed attachment since found a bug!