fix(junit): resolve datasource placeholders with bounded expansion

[y-ok]

Summary

• resolve ${...} datasource placeholders in TestResourceContext using system properties, environment variables, and loaded properties
• keep placeholder resolution bounded with an iteration limit to avoid non-terminating expansion
• add tests for system property/environment/property fallback, non-string keys, and iteration-limit behavior
• bump project versions to 0.2.2

Verification

• mvn clean test (BUILD SUCCESS)
• Coverage (JaCoCo)
  • flexdblink: INSTRUCTION 100% (19515/19515), BRANCH 100% (2086/2086)
  • flexdblink-maven-plugin: INSTRUCTION 100% (1409/1409), BRANCH 100% (164/164)