Diktat runner

### What's done:
- main runner

It closes #1685

diktat-cli/src/main/kotlin/org/cqfn/diktat/DiktatMainRunner.kt

@@ -0,0 +1,66 @@
+package org.cqfn.diktat
+
+import org.cqfn.diktat.api.DiktatRuleSet
+import org.cqfn.diktat.api.DiktatRuleSetFactory
+import org.cqfn.diktat.ktlint.DiktatProcessorFactoryImpl
+import org.cqfn.diktat.ruleset.rules.DiktatRuleSetFactoryImpl
+import mu.KotlinLogging
+import org.apache.logging.log4j.LogManager
+import org.apache.logging.log4j.core.LoggerContext
+import org.slf4j.event.Level
+
+private val log = KotlinLogging.logger { }
+
+fun main() {
+    // a temporary
+    val logLevel = Level.ERROR
+    // set log level
+    LogManager.getContext(false)
+        .let { it as LoggerContext }
+        .also { ctx ->
+            ctx.configuration.rootLogger.level = when (logLevel) {
+                Level.ERROR -> org.apache.logging.log4j.Level.ERROR
+                Level.WARN -> org.apache.logging.log4j.Level.WARN
+                Level.INFO -> org.apache.logging.log4j.Level.INFO
+                Level.DEBUG -> org.apache.logging.log4j.Level.DEBUG
+                Level.TRACE -> org.apache.logging.log4j.Level.TRACE
+            }
+        }
+        .updateLoggers()
+
+    // default implementations
+    val diktatRuleSetFactory = DiktatRuleSetFactoryImpl()
+    val diktatProcessorFactory = DiktatProcessorFactoryImpl()
+
+    // ruleSet
+    val diktatRuleSet: DiktatRuleSet = diktatRuleSetFactory()
+    val diktatProcessor: DiktatProcessor = diktatProcessorFactory(diktatRuleSet)
+
+    val code = mutableListOf<String>()
+    while (true) {
+        val line = readln()
+        if (line == "CHECK") {
+            diktatProcessor.check(
+                code = code.joinToString(),
+                isScript = true
+            ) { error, _ ->
+                println(error.toString())
+            }
+            code.clear()
+        } else if (line == "FIX") {
+            val result = diktatProcessor.fix(
+                code = code.joinToString(),
+                isScript = true
+            ) { error, _ ->
+                println(error.toString())
+            }
+            code.clear()
+            println("Formatted code:")
+            println(result)
+        } else if (line == "END") {
+            break
+        } else {
+            code.add(line)
+        }
+    }
+}