naming optimizations

[Nic30]

• Prefix for HCL objects needs to be specific so it is more easy to automatically update code after library updates

  • visually separation of normal Python objects and HCL
  • simplifies search in code

• [x] Names of signal, interface or component

  • Involves: BasicRtlSimProxy, RtlSignal, HwIO, HwModule
  • now it is not clear what the name actually means
    • .name -> ._name - logical name, name from user description
    • ._name -> ._hdlName - physical name, full name with resolved name collisions etc.

• [ ] Backward type reference of signals and constant

• type property name is too long ._dtype -> ._ht

• [ ] Split HConst and HVar classes (because of performance reasons)

  
  def tv(signal):
  return signal._dtype.getConstCls()

class RtlSignalOps(): def invert(self): return self.naryOp(AllOps.NOT, tv(self).invert)

currently the const class contains code also for signal/variable operator

class BitsConst: def invert(self): if isinstance(self, HConst): return Bits3val.invert(self) else: ...

- [x] Bits -> HBits  (act as an int but it is not named int to avoid things like float inheriting from int)
- [x] hwt.synthesizer.unit.Unit -> hwt.hModule.HwModule (Using module stem because it is more widely used)
  - [x] ._interfaces -> ._hwIOs
  - [x] ._subunits -> ._subHwModules
  - [x] ._params -> ._hwParams 
  - [x] ._paramsShared() -> ._hwParamsShared() 
- [x] Interface -> HwIO
- [x] Signal -> HwIOSignal (adding HwIO so user do not think that this is the signal instance which should be normally used for communication inside of module)
- [x] Param -> HwParam
- [x] HValue -> HConst (same convention as in LLVM)
- [x] Operator -> HOperatorNode
- [x] OpDefinition ->  HOperatorNodeDef
- [x] AllOps -> HwtOps
- [x] UniqList -> SetList (same convention as in LLVM)
- [x] SimTestCase.u -> SimTestCase.dut (replacing u after Unit -> HModule)
- [x] EmptyUnit -> hwtLib.abstract.emptyHModule.EmptyHModule
- [x] hwt.synthesizer.utils -> hwt.synth
- [x] HsStructIntf -> HwIOStructVldRd
- [x] StructIntf -> HwIOStruct 
- [x] VldSyncedStructIntf -> HwIOStructVld
- [x] RdSyncedStruct -> HwIOStructRd 
- [x] HdlType_to_Interface -> HdlType_to_HwIO
- [x] Interface_to_HdlType -> HwIO_to_HdlType 
- [x] DifferentialIntf -> HwIODifferentialSig
- [x] RegCntrl -> HwIORegCntrl 
- [x] TristateSig -> HwIOTristateSig
- [x] UnionSink -> HwIOUnionSink
- [x] UnionSource -> HwIOUnionSource
- [x] RdSynced -> HwIODataRd
- [x] RdSync -> HwIORdSync
- [x] VldSynced -> HwIODataVld
- [x] VldSync -> HwIOVldSync
- [x] Handshaked -> HwIODataVldRd
- [x] HandshakeSync -> HwIOVldRdSync
- [x] Clk -> HwIOClk
- [x] Rst -> HwIORst
- [x] Rst_n -> HwIORst_n
- [x] ReqDoneSync -> HwIOReqDoneSync
- [x] BramPort_withoutClk -> HwIOBramPort_noClk
- [x] BramPort -> HwIOBramPort
- [x] FifoWriter -> HwIOFifoWriter
- [x] FifoReader -> HwIOFifoReader
- [x] AxiStream -> Axi4Stream
- [x] hwtLib.amba.axi_intf_common -> hwtLib.amba.axi_common  
- [x] walkPhysInterfaces -> HwIO_walkSignals
- [x] walkFlatten -> HwIO_walkFlatten
- [x] packHwIO -> HwIO_pack
- [x] connectPacked -> HwIO_connectPacked 
- [x] IntfIpMetaNotSpecified -> IntfIpMetaNotSpecifiedError

flatten to parent:
* move constants from hwt.synthesizer.rtlLevel.constants, hwt.hdl.constants to hwt.constants
* hwt.synthesizer.interfaceLevel.interfaceUtils
* hwt.synthesizer.rtlLevel.signalUtils 
   * walkers -> rtlSignalWalkers
   * ops -> rtlSignalOps
* hwt.synthesizer.hObjList -> hwt.hObjList