[BWC and API enforcement] Define the initial set of annotations, their meaning and relations between them

[reta]

Is your feature request related to a problem? Please describe.
It would make sense to start with this 4 annotations (please see their description for the guarantees)

Describe the solution you'd like

/**
 * Stable public APIs that retain source and binary compatibility within a minor release.
 * These interfaces can change from one major release to another major release
 * (e.g. from 1.0 to 2.0). The types marked with this annotations could only expose
 * other {@link PublicApi} or {@link ExperimentalApi} types as public members.
 */
@Documented
@Target({ ElementType.TYPE, ElementType.PACKAGE, ElementType.METHOD, ElementType.CONSTRUCTOR })
public @interface PublicApi {

}

/**
 * Experimental APIs that may not retain source and binary compatibility within major,
 * minor or patch releases. The types marked with this annotations could only expose
 * other {@link PublicApi} or {@link ExperimentalApi} types as public members.
 */
@Documented
@Target({ ElementType.TYPE, ElementType.PACKAGE, ElementType.METHOD, ElementType.CONSTRUCTOR })
public @interface ExperimentalApi {

}

/**
 * Internal APIs that have no compatibility guarantees and should not be used outside
 * of OpenSearch core components.
 */
@Documented
@Target({ ElementType.TYPE, ElementType.PACKAGE, ElementType.METHOD, ElementType.CONSTRUCTOR })
public @interface InternalApi {

}

/**
 * Marks the public APIs as deprecated and scheduled for removal in one of the upcoming
 * major release. The types marked with this annotations could only be other {@link PublicApi}s.
 */
@Documented
@Target({ ElementType.TYPE, ElementType.PACKAGE, ElementType.METHOD, ElementType.CONSTRUCTOR })
public @interface DeprecatedApi {
    String since();
    String forRemoval();
}

Describe alternatives you've considered
N/A

Additional context
Part of #8127