[FEATURE] Add @ConstExpr Annotation for build-time code-execution for java

[Michael1297]

Describe the feature
Simulates constexpr from C++11, build-time code-execution, from cppreference.com:

The @ConstExpr Annotation declares that it is possible to evaluate the value of the function or variable at compile time.

@ConstExpr
private static final long BUILD_TIME = System.currentTimeMillis();
@ConstExpr
private static final String SIMPLE_NAME = MyClass.class.getSimpleName();

// is replaced with:
private static final long BUILD_TIME = 1739114746283L; // value is an example, depends on when you run
private static final String SIMPLE_NAME = "MyClass";

@ConstExpr
private static final int MAX_WIDTH = Integer.parseInt(getProperties().getProperty("width", "1000"));
@ConstExpr
private static final int MAX_HEIGHT = Integer.parseInt(getProperties().getProperty("height", "1000"));    

private static Properties getProperties() {
    Properties properties = new Properties();
    try (FileInputStream fileInputStream = new FileInputStream(PROJECT_PROPERTIES_PATH)) {
        properties.load(fileInputStream);
    } catch (Exception e) {
        LOGGER.err("File not found: " + PROJECT_PROPERTIES_PATH);
    }
    return properties;
}

// is replaced with:
private static final int MAX_WIDTH = 5000;
private static final int MAX_HEIGHT = 5000;    

Describe the target audience
This feature would benefit Java developers developing mobile apps and games.

Additional context
Java libraries that implement this function:
https://github.com/junkdog/constexpr-java (unavailable in the maven repository)
https://github.com/Sipkab/jvm-constexpr (does not support maven/gradle)

Mention of this function
https://www.reddit.com/r/java/comments/5aci2a/constexprjava_buildtime_codeexecution_using_the/
https://discuss.kotlinlang.org/t/string-literals-way-to-compute-hashcode-at-compile-time/23745
https://youtrack.jetbrains.com/issue/KT-14652
https://discuss.kotlinlang.org/t/feature-request-compile-time-code-generator-annation/13719