feat: rewrite the implementation into Kotlin

[KengoTODA]

Translate codes in src/main/groovy into Kotlin.

BREAKING CHANGE: This plugin has been rewritten in Kotlin, and it may break the binary compatibility of public API. Intentional changes are listed as follows:

Changes for Groovy buildscripts

About effort and reportLevel properties of SpotBugsTask and SpotBugsExtension, Groovy buildscripts should use use valueOf(String) method explicitly. This limitation is caused by a known issue of the Groovy language:

// before (v5)
spotbugs {
    effort = 'default'
    reportLevel = 'default'
}

// after (v6)
spotbugs {
    effort = Effort.valueOf('DEFAULT')
    reportLevel = Confidence.valueOf('DEFAULT')
}

Changes for Kotlin buildscripts

It is recommended to use Gradle 8.2 or later, then you can enjoy the simple property assignment feature by default:

// legacy (Gradle 8.1 and older)
import com.github.spotbugs.snom.Confidence
import com.github.spotbugs.snom.Effort

spotbugs {
    effort.set(Effort.DEFAULT)
    reportLevel.set(Confidence.DEFAULT)
}

// new (Gradle 8.2 and later)
import com.github.spotbugs.snom.Confidence
import com.github.spotbugs.snom.Effort

spotbugs {
    effort = Effort.DEFAULT
    reportLevel = Confidence.DEFAULT
}

It is also possible to use string values, however, it is not recommended due to lack of type-safety:

// new (Gradle 8.2 and later)
import com.github.spotbugs.snom.assign

spotbugs {
    effort = "DEFAULT"
    reportLevel = "DEFAULT"
}

[KengoTODA]

Illegal bytecode found from my local build:

* What went wrong:
A problem occurred evaluating root project '1691283557801-0'.
> Could not create task ':spotbugsMain'.
   > Could not create task of type 'SpotBugsTask'.
      > Bad type on operand stack
        Exception Details:
          Location:
            com/github/spotbugs/snom/SpotBugsTask_Decorated.getIgnoreFailures()Z @36: ireturn
          Reason:
            Type 'org/gradle/api/provider/Property' (current frame, stack[0]) is not assignable to integer
          Current Frame:
            bci: @36
            flags: { }
            locals: { 'com/github/spotbugs/snom/SpotBugsTask_Decorated', 'org/gradle/api/provider/Property' }
            stack: { 'org/gradle/api/provider/Property' }
          Bytecode:
            0x0000000: 2ab4 01fc 4c2b c700 1d2a b601 d02a 1301
            0x0000010: 0413 01ec 1301 feb6 01f1 c001 ec4c 2a2b
            0x0000020: b501 fc2b ac                           
          Stackmap Table:
            append_frame(@35,Object[#492])

[KengoTODA]

refs #640

[github-advanced-security]

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[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
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5.5% Coverage
0.0% Duplication

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[github-actions]

🎉 This PR is included in version 6.0.0-v6.1 🎉

The release is available on:

• 6.0.0-v6.1
• GitHub release

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[github-actions]

🎉 This PR is included in version 6.0.0-beta.1 🎉

The release is available on:

• 6.0.0-beta.1
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[github-actions]

🎉 This PR is included in version 6.0.0-rc.1 🎉

The release is available on:

• 6.0.0-rc.1
• GitHub release

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[github-actions]

🎉 This PR is included in version 6.0.0 🎉

The release is available on:

• 6.0.0
• GitHub release

Your semantic-release bot 📦🚀