…same as NEURON only (#1192)

* See the corresponding change in CoreNEURON:
   BlueBrain/CoreNeuron@c432c13
* This change implements following improvements for CoreNEURON usage:
  - CoreNEURON direct mode does not do its own version of finitialize().
  - On entry to CoreNEURON, all state needed to continue a simulation
    is copied from NEURON (including Event Queue).
  - On exit from CoreNEURON all state needed to continue the simulation
    in NEURON is copied from CoreNEURON (including EventQueue)
* Implementation for copying event queue back to NEURON.
* Updated testcorenrn with more test: neuronsimulator/testcorenrn#5
* Updated coreneuron submodule: BlueBrain/CoreNeuron#528
* Update rst documentation for the new change
* Increase error verbosity for CI debugging.
* h.nrnmpi_init() must be called early to avoid mpi error on exit.
* Add more tests for net_move, net_send and watch statements
* Add tests for neuron<->coreneuron alternate execution
* Test of multiple activated WATCH statements.
  - Note: only one can be triggered at a time.
* psolve transfer corenrn ->  nrn calls bbcore_read in nrn.
  - This is needed at least to update nrnran123 sequence state
    in order to be able to continue psolve on either side.
    Updated coreneuron and testcorenrn.
* Global methods to set and get HOC Random123 sequence.
      int nrn_random123_setseq(Rand* r, uint32_t seq, char which);
      int nrn_random123_getseq(Rand* r, uint32_t* seq, char* which);
    Update external/coreneuron
    Extend a couple tests for psolve.
* Spike transfer from CoreNEURON should append to spike vectors.
    Begin extending tests involving psolve with CoreNERUON to verify
    that psolve is restartable.
* Framework for copying event queue back to NEURON.
* Event Queue NEURON->CoreNEURON NetCon, Presyn, SelfEvent


Co-authored-by: Alexandru S�<83>vulescu <alexandru.savulescu@epfl.ch>
Co-authored-by: Michael Hines <michael.hines@yale.edu>
Co-authored-by: Olli Lupton <oliver.lupton@epfl.ch>
Co-authored-by: Pramod Kumbhar <pramod.s.kumbhar@gmail.com>

Closes #1066
Closes #826

See neuronsimulator/testcorenrn#5