test: EXPOSED-941 Bump to JUnit 5 in all test suites & JUnit 6 where possible

[bog-walk]

Description

Summary of the change:

1. Migrate from org.junit.* (JUnit 4) to at minimum org.junit.jupiter.* (JUnit 5)
2. Bump to JUnit 6 in all modules that already have JDK 17 as minimum requirement (Spring modules + Encryption module)

Detailed description:

• Why: Predominantly to align with new minimum requirements for upcoming Spring Framework 7 bump.

• How:

  • Introduce both JUnit 5 & Junit 6 dependencies.
  • All test suites, including exposed-tests and exposed-r2dbc-tests now depend on JUnit 5.
    • Replace all usages of org.junit.Test with org.junit.jupiter.api.Test
    • Replace @Before & @After with @BeforeEach & @AfterEach
    • Replace all usages of Assume & Assert with Assumptions & Assertions
    • Migrate from TemporaryFolder() rule to @TempDir
    • Migrate to use parameterized classes via @ParameterizedClass
    • Replace @Test(expected = …​) with Assert.assertThrows
    • Replace @Test(timeout = ...) with @Timeout
    • Migrate from custom rule for repeated test to new @RepeatedTest
    • Migrate away from CoroutinesTimeout() rule (different workarounds depending on case)
    • Replace Spring @RunWith(SpringJUnit4ClassRunner::class) with @ExtendWith(SpringExtension::class)
    • Replace Spring @FixMethodOrder with @TestMethodOrder
  • spring-transaction, exposed-spring-boot-starter, & exposed-crypt now depend on JUnit 6.

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Type of Change

Please mark the relevant options with an "X":

• Other - Dependency (Test) bump

Affected databases:

• All

Checklist

• Unit tests are in place
• The build is green (including the Detekt check)
• All public methods affected by my PR has up to date API docs

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Related Issues

EXPOSED-946
EXPOSED-941

[bog-walk]

@e5l This PR might not be fully ready 🤔

I'm trying to understand this successful build that is showing a significant drop in test amount, but took almost 20 minutes longer overall.
In IDEA test output, JUnit 5 does group tests from a single class in a drop down, so I'm trying to confirm that's what's happening here on TC too. When I go through the build log, it does seem like all tests are being run...

But it's so slow, I'm wondering if there's an extra setup step I've missed.

[bog-walk]

I added the platform launcher to check but the successful build is consistent. The only place I haven't looked is in TC config itself, to see if it has some setting for how tests are being counted/reported, or if there's some way to ungroup them.

I'm looking into the failing Detekt btw. Passes locally & message is unhelpful, so I have to pass through to confirm.

[e5l]

It shows 15 runs for test, I guess it means multiple runs for the different platforms

[e5l]

lgtm