Change artifact names to module names (BREAKING CHANGE)

[tlinkowski]

Apply @sormuras' naming convention to this project:

• basic-annotations -> pl.tlinkowski.annotation.basic
• sample-java-api -> pl.tlinkowski.annotation.sample.api (was: pl.tlinkowski.sample.api)
• sample-kotlin-usage -> pl.tlinkowski.annotation.sample.usage.kotlin (was: pl.tlinkowski.sample.usage)
• sample-java-usage -> pl.tlinkowski.annotation.sample.usage.java (was: pl.tlinkowski.sample.usage)

Related to tlinkowski/tlinkowski-superpom#64.