list different cases requiring different SBOMs

Signed-off-by: Hervé Boutemy <hboutemy@apache.org>

examples/README.md

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+Example Projects
+================
+
+## Libraries
+
+Typical default case is a library, with `jar` [packaging](https://maven.apache.org/guides/introduction/introduction-to-the-lifecycle.html#Packaging) (default packaging when not specified in `pom.xml`),
+`target/*.jar` output file built by `maven-jar-plugin`:
+- Maven dependencies of the library are pure symbolic references defined in `pom.xml` and version is just **preferred**
+  (unless defined as `[x.y.z]` in `pom.xml`),
+- consumer of the library will get its dependencies as **transitive** dependencies of the library added and ,
+- version of transitives are calculated by the built tool, based on consuming context: many aspects influence effective
+  version, including `dependencyManagement` configuration and eventual conflicts between different transitives
+
+See Maven's [Introduction to Dependency Mechanism](https://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html)
+for more details.
+
+Also don't be confused:
+- a Maven `<dependency>` is a [CycloneDX `component`](https://cyclonedx.org/docs/1.6/json/#components):
+  a [CycloneDX `dependency`](https://cyclonedx.org/docs/1.6/json/#dependencies) is a Maven's dependency tree node,  
+- Maven's [dependency scope](https://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#Dependency_Scope)
+  (`compile`, `provided`, `runtime`, `test`) is not a [CycloneDX scope](https://cyclonedx.org/docs/1.6/json/#components_items_scope)
+  (`required`, `optional`, `excluded`),
+- Maven's [BOM POM](https://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#bill-of-materials-bom-poms)
+(used to import dependencyManagement `<dependencyManagement><scope>import</scope>`) is not a (CycloneDX) SBOM,
+
+## Java EE
+
+Java EE provide packaging archives formats where dependency components are copied:
+
+- `war` web archives, created by [`maven-war-plugin`](https://maven.apache.org/plugins/maven-war-plugin/) often through
+  `war` packaging, with `*.jar` dependencies embedded in `WEB-INF/lib`,
+- `ejb` (with client), `rar`, `par`, `acr`...
+- `ear` enterprise archives, created by [`maven-ear-plugin`](https://maven.apache.org/plugins/maven-ear-plugin/), with
+  flexible [EAR modules](https://maven.apache.org/plugins/maven-ear-plugin/modules.html) defining how libs are packaged.
+
+### Frontend
+
+https://github.com/eirslett/frontend-maven-plugin
+
+## Maven Assembly
+
+Flexible archive creation done by [`maven-assembly-plugin`](https://maven.apache.org/plugins/maven-assembly-plugin/),
+with optional [`dependencySet` configuration](https://maven.apache.org/plugins/maven-assembly-plugin/assembly.html#class_dependencySet).
+
+### Provisio
+
+[Provisio](https://github.com/jvanzyl/provisio) is another plugin trying to provide equivalent features.
+
+## Maven Shade
+
+[Maven Shade Plugin](https://maven.apache.org/plugins/maven-shade-plugin/) provides the capability to package the
+artifact in an uber-jar, including its dependencies and to shade - i.e. rename - the packages of some of the dependencies.
+
+It provides a very flexible way to [select content](https://maven.apache.org/plugins/maven-shade-plugin/examples/includes-excludes.html)
+from dependencies.
+
+## Executable Jars
+
+- [Spring Boot `repackage`](https://docs.spring.io/spring-boot/maven-plugin/packaging.html)
+- [Spring Boot OCI Images](https://docs.spring.io/spring-boot/maven-plugin/build-image.html)
+- [Uni-Jar](https://github.com/nsoft/uno-jar)
+- [App Assembler](https://www.mojohaus.org/appassembler/appassembler-maven-plugin/index.html)