CORDA-1764: Make shell use picocli for parsing command line options (#3923)

* Fix link in shell documentation

* The TypeSafe config parser wants extensions.sshd to be present in the config even though extensions is nullable

* Temp commit

* Make Standalone Shell use picocli

* Simplify gradle config for bootstrapper

* Fix logging dependency issues

* Revert "Temp commit"

This reverts commit f4efafcc9d.

* Fix quasarExcludeExpression

* Correct bootstrapper configuration

* Correct CRaSH capitalisation in docs

* Fix unit tests

* Fix help text typo

* Make logging level case insensitive

* Fix CRaSH capitalisation in help text

* Fix unit tests

node/src/main/kotlin/net/corda/node/internal/NodeStartup.kt

@@ -456,7 +456,7 @@ open class NodeStartup: CordaCliWrapper("corda", "Runs a Corda Node") {
     }
 
     override fun initLogging() {
-        val loggingLevel = loggingLevel.name().toLowerCase(Locale.ENGLISH)
+        val loggingLevel = loggingLevel.name.toLowerCase(Locale.ENGLISH)
         System.setProperty("defaultLogLevel", loggingLevel) // These properties are referenced from the XML config file.
         if (verbose) {
             System.setProperty("consoleLogLevel", loggingLevel)

node/src/test/kotlin/net/corda/node/NodeCmdLineOptionsTest.kt

@@ -3,10 +3,10 @@ package net.corda.node
 import net.corda.core.internal.div
 import net.corda.node.internal.NodeStartup
 import net.corda.nodeapi.internal.config.UnknownConfigKeysPolicy
-import org.apache.logging.log4j.Level
 import org.assertj.core.api.Assertions.assertThat
 import org.junit.BeforeClass
 import org.junit.Test
+import org.slf4j.event.Level
 import java.nio.file.Path
 import java.nio.file.Paths