Build logic for pgjdbc

This is a subset of extra plugins for factoring out the common patterns from the common build logic.

The recommended approach is to use build composition, so every build script should list all its prerequisites in the top-most plugins { ... } block.

The use of allprojects and subprojects is an anti-pattern as it makes it hard to identify the configuration for a given project.

Let us consider an example (see /pgjdbc/build.gradle.kts):

plugins {
    id("build-logic.java-published-library")
    id("build-logic.test-junit5")
}

...

It means that we deal with a Java library that will be published to Central, and which uses JUnit 5 for testing.

If you want to see what the logic does, you could open build-logic.java-published-library.gradle.kts and buildlogic.test-junit5.gradle.kts.