Add the ability to configure ignoredFiles

[kpagratis]

It would be useful to have the ability to configure files to be ignored by the plugin.
With this functionality, you could filter files like markdown docs so your pipelines can run faster.

[CLAassistant]

All committers have signed the CLA.

[joshafeinberg]

@kpagratis thanks for the contribution, can you please run ktlint locally to get some fixes in for your changes then I can probably get this in for the next release :)

[kpagratis]

@joshafeinberg Yes of course. I'll do that tomorrow. Thanks for taking a look!

[kpagratis]

❯ ./gradlew ktlintCheck Deprecated Gradle features were used in this build, making it incompatible with Gradle 8.0. You can use '--warning-mode all' to show the individual deprecation warnings and determine if they come from your own scripts or plugins. See https://docs.gradle.org/7.4.2/userguide/command_line_interface.html#sec:command_line_warnings BUILD SUCCESSFUL in 339ms 1 actionable task: 1 up-to-date ❯ ./gradlew ktlintFormat Deprecated Gradle features were used in this build, making it incompatible with Gradle 8.0. You can use '--warning-mode all' to show the individual deprecation warnings and determine if they come from your own scripts or plugins. See https://docs.gradle.org/7.4.2/userguide/command_line_interface.html#sec:command_line_warnings BUILD SUCCESSFUL in 324ms 1 actionable task: 1 up-to-date 

[joshafeinberg]

Whoops, looks we applied ktlint wrong so i'll merge this and then fix that up. Thanks again