Allow ORT to deal with Maven dependencies that only differ in the classifier

[sschuberth]

See the case at https://github.com/eclipse/dash-licenses/issues/16#issuecomment-631545035. This is something we should investigate, too.

[sschuberth]

Another such example is also mentioned at https://github.com/clearlydefined/service/issues/786.

[sschuberth]

FYI, here's some general information about classifiers.

[sschuberth]

As an interesting side-effect of this limitation, ORT might run into an endless recursion when traversing dependencies:

E.g. the netty-tcnative-boringssl-static artifact (which does not have a classifier) depends on several equally named artifacts with classifiers, like

<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-tcnative-boringssl-static</artifactId>
    <version>2.0.56.Final</version>
    <classifier>linux-x86_64</classifier>
    <scope>compile</scope>
</dependency>
<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-tcnative-boringssl-static</artifactId>
    <version>2.0.56.Final</version>
    <classifier>linux-aarch_64</classifier>
    <scope>compile</scope>
</dependency>

As ORT disregards the classifier, it looks to ORT as if the artifacts would depend on itself.