refactor(Gradle): Avoid the use of {all,sub}projects altogether

See [1] for background information.

[1]: https://docs.gradle.org/current/userguide/sharing_build_logic_between_subprojects.html#sec:convention_plugins_vs_cross_configuration

Signed-off-by: Sebastian Schuberth <sebastian@doubleopen.org>

build.gradle.kts

@@ -91,7 +91,7 @@ tasks.named<DependencyUpdatesTask>("dependencyUpdates") {
 // all dependencies at once is beneficial, e.g. for debugging version conflict resolution.
 // [1]: https://docs.gradle.org/current/userguide/viewing_debugging_dependencies.html#sec:listing_dependencies
 tasks.register("allDependencies") {
-    val dependenciesTasks = allprojects.map { it.tasks.named<DependencyReportTask>("dependencies").get() }.sorted()
+    val dependenciesTasks = getTasksByName("dependencies", /* recursive = */ true).sorted()
     dependsOn(dependenciesTasks)
 
     // Ensure deterministic output by requiring to run tasks after each other in always the same order.

buildSrc/src/main/kotlin/ort-plugins-conventions.gradle.kts

@@ -35,7 +35,7 @@ dependencies {
     // their own.
     val embeddedProjects = setOf("gradle-plugin", "web-app-template")
 
-    project.subprojects.filter {
+    childProjects.values.filter {
         it.name !in embeddedProjects
     }.forEach {
         api(it)