Separate main function from MainCommand

[jan-goral]

In an abstract way, the main function is a typical entry point for any jvm application. The CLI is one of the possible options for how the user can interact with the application. Those are two different things and should be separated.

Author the user story for this feature

As a developer, I want to have separated the main function from the picocli MainComand due to the SRP rule.

Describe the solution

the ftl.Main.kt file should contain only the entry point function:

fun main(args: Array<String>) {
    withGlobalExceptionHandling {
        CommandLine(Main()).execute(*args)
    }
}

Everything else, related to picocli command should go to the ftl.cli.MainCommand.kt