Ensure correct connect and disconnect functionality

• move IntList to TestUtils
• make resolve-element for wildcard connections a method (instead of an attribute). would never be a cache-hit anyway
• extend base.clean to remove generated aspects as well
• fixing imports
• introduced new types to encapsulate behaviour: RagConnectTokenMap, RagConnectPublisher
• move lastValue (of sendDefinitions) into new publisher
• create connectToken outside of handlers
• MqttHandler:
  • make wildcardPatterns a list
  • added Lock to avoid simultaneous access/modification of AST
• RestHandler: update dependency requirement to Spark 3.9.3 in order to unmap existing routes upon disconnect
• testing disconnect functionality in (most) existing tests

Closes #31 (closed)

ragconnect.base/src/main/jastadd/Errors.jrag

-import java.util.Set;
-import java.util.TreeSet;
-import java.util.LinkedList;
-
 aspect Errors {
   coll Set<ErrorMessage> RagConnect.errors()
     [new TreeSet<ErrorMessage>()]