Replace use of SyncVar with Ref (support scala 2.13)

[Tomislav Grospić]

Overview

In Scala 2.13 SyncVar is removed so we need to switch to alternative. Another reason is to use functional abstraction which is Ref[F, A] from cats library.

Solution

Replace objects defined as SyncVar with Ref concurrent mutable reference.
Each item should be in a separate PR.

• Replace objects to store report events in Reporting RSpace.
  #3735
  

  rchain/rspace/src/main/scala/coop/rchain/rspace/ReportingRspace.scala

  Lines 114 to 115 in 2a52bd8

   val report: SyncVar[Seq[Seq[ReportingEvent]]] = create[Seq[Seq[ReportingEvent]]](Seq.empty) 
   val softReport: SyncVar[Seq[ReportingEvent]]  = create[Seq[ReportingEvent]](Seq.empty) 

• Replace eventLog reference in RSpace base class.
  #3736
  

  rchain/rspace/src/main/scala/coop/rchain/rspace/RSpaceOps.scala

  Line 57 in 8b9e315

   protected[this] val eventLog: SyncVar[EventLog] = create[EventLog](Seq.empty) 

• Replace produceCounters reference in RSpace base class. This one is little more involved. COMM constructor should return wrapped COMM object to calculate timesRepeated with F result.
  

  rchain/rspace/src/main/scala/coop/rchain/rspace/RSpaceOps.scala

  Line 58 in 8b9e315

   protected[this] val produceCounter: SyncVar[Map[Produce, Int]] = 

• Replace installs reference in RSpace base class.
  

  rchain/rspace/src/main/scala/coop/rchain/rspace/RSpaceOps.scala

  Lines 87 to 91 in 8b9e315

   private[this] val installs: SyncVar[Installs[F, C, P, A, K]] = { 
     val installs = new SyncVar[Installs[F, C, P, A, K]]() 
     installs.put(Map.empty) 
     installs 
   } 

• replace SyncVar with LinkedBlockingQueue as lock in Transport Layer test.
  

  rchain/comm/src/test/scala/coop/rchain/p2p/EffectsTestInstances.scala

  Lines 65 to 67 in aad68bd

   var reqresp: Option[Responses] = None 
   var requests: List[Request]    = List.empty[Request] 
   val lock                       = SyncVarOps.create[TransportLayerStub[F]](this)