SourceTask in Gradle plugin

[nulls]

What's done:

• migrated to SourceTask
• removed inputs

It closes #1026

[github-actions[bot]]

JUnit Tests (macOS, EnricoMi/publish-unit-test-result-action@v2)

2 files   -    163  2 suites   - 163   7s :stopwatch: - 5m 34s 5 tests  - 1 390  5 :heavy_check_mark:  - 1 354  0 :zzz:  - 36  0 :x: ±0  5 runs   - 2 769  5 :heavy_check_mark:  - 2 733  0 :zzz:  - 36  0 :x: ±0 

Results for commit 2f373664. ± Comparison against base commit 7b7d2b6f.

This pull request removes 1390 tests.

``` com.saveourtool.diktat.plugin.gradle.DiktatGradlePluginTest ‑ check default extension properties() com.saveourtool.diktat.plugin.gradle.DiktatGradlePluginTest ‑ check default reporter type value() com.saveourtool.diktat.plugin.gradle.DiktatGradlePluginTest ‑ check that tasks are registered() com.saveourtool.diktat.plugin.gradle.DiktatJavaExecTaskTest ‑ check command line for various inputs() com.saveourtool.diktat.plugin.gradle.DiktatJavaExecTaskTest ‑ check command line has reporter type and output() com.saveourtool.diktat.plugin.gradle.DiktatJavaExecTaskTest ‑ check command line has reporter type without output() com.saveourtool.diktat.plugin.gradle.DiktatJavaExecTaskTest ‑ check command line in debug mode() com.saveourtool.diktat.plugin.gradle.DiktatJavaExecTaskTest ‑ check command line in githubActions mode() com.saveourtool.diktat.plugin.gradle.DiktatJavaExecTaskTest ‑ check command line with excludes() com.saveourtool.diktat.plugin.gradle.DiktatJavaExecTaskTest ‑ check command line with non-existent inputs() … ```

:recycle: This comment has been updated with latest results.

[github-actions[bot]]

JUnit Tests (Windows, EnricoMi/publish-unit-test-result-action@v2)

2 files   -    163  2 suites   - 163   15s :stopwatch: - 12m 51s 5 tests  - 1 390  5 :heavy_check_mark:  - 1 373  0 :zzz:  - 17  0 :x: ±0  5 runs   - 2 769  5 :heavy_check_mark:  - 2 752  0 :zzz:  - 17  0 :x: ±0 

Results for commit 2f373664. ± Comparison against base commit 7b7d2b6f.

This pull request removes 1390 tests.

``` com.saveourtool.diktat.plugin.gradle.DiktatGradlePluginTest ‑ check default extension properties() com.saveourtool.diktat.plugin.gradle.DiktatGradlePluginTest ‑ check default reporter type value() com.saveourtool.diktat.plugin.gradle.DiktatGradlePluginTest ‑ check that tasks are registered() com.saveourtool.diktat.plugin.gradle.DiktatJavaExecTaskTest ‑ check command line for various inputs() com.saveourtool.diktat.plugin.gradle.DiktatJavaExecTaskTest ‑ check command line has reporter type and output() com.saveourtool.diktat.plugin.gradle.DiktatJavaExecTaskTest ‑ check command line has reporter type without output() com.saveourtool.diktat.plugin.gradle.DiktatJavaExecTaskTest ‑ check command line in debug mode() com.saveourtool.diktat.plugin.gradle.DiktatJavaExecTaskTest ‑ check command line in githubActions mode() com.saveourtool.diktat.plugin.gradle.DiktatJavaExecTaskTest ‑ check command line with excludes() com.saveourtool.diktat.plugin.gradle.DiktatJavaExecTaskTest ‑ check command line with non-existent inputs() … ```

:recycle: This comment has been updated with latest results.

[nulls]

The comment from the original is about returning back files to have a common configuration with detekt to have a common configuration for such projects.

Spotless uses FileCollection as input and ~it does support ant patterns, but doesn't support exclusion~ uses a specific methods to support ant patterns. ~Need to try to use both of them...~