Add Java implementation (ulid-creator)

[fabiolimace]

This PR adds a library that implements the ULID spec.

ULID Creator

ULID Creator is a Java library that generates ULIDs

Project on Github: https://github.com/f4b6a3/ulid-creator

How to Use

Create a ULID:

Ulid ulid = UlidCreator.getUlid();

Create a Monotonic ULID:

Ulid ulid = UlidCreator.getMonotonicUlid();

Maven dependency

Add these lines to your pom.xml.

<!-- https://search.maven.org/artifact/com.github.f4b6a3/ulid-creator -->
<dependency>
  <groupId>com.github.f4b6a3</groupId>
  <artifactId>ulid-creator</artifactId>
  <version>4.1.2</version>
</dependency>

See more options in maven.org.

Other usage examples

Create a ULID from a canonical string (26 chars):

Ulid ulid = Ulid.from("0123456789ABCDEFGHJKMNPQRS");

Convert a ULID into a canonical string in upper case:

String string = ulid.toString(); // 0123456789ABCDEFGHJKMNPQRS

Convert a ULID into a canonical string in lower case:

String string = ulid.toLowerCase(); // 0123456789abcdefghjkmnpqrs

Convert a ULID into a UUID:

UUID uuid = ulid.toUuid(); // 0110c853-1d09-52d8-d73e-1194e95b5f19

Convert a ULID into a RFC-4122 UUID v4:

UUID uuid = ulid.toRfc4122().toUuid(); // 0110c853-1d09-42d8-973e-1194e95b5f19
                                       //               ^ UUID v4

Convert a ULID into a byte array:

byte[] bytes = ulid.toBytes(); // 16 bytes (128 bits)

Get the creation instant of a ULID:

Instant instant = ulid.getInstant(); // 2007-02-16T02:13:14.633Z

[aadrian]

@alizain any chance merging these PRs?

Thank you.