Updated heatTransfer write part: common handling filename argument; uses PutDeferred and skips PerformPuts

Refactored heat transfer example. A config file is now command line argument. Reader's decomposition is also command line argument.

    read_fileonly/ contains the file reader examples,
    read/ contains the streaming version,
    writer and reader is using heat.xml config file from the root directory

Attempting to solve HDF5 failed tests on summitdev

InquireVariable/Attribute working for valid name, but returning invalid
type

ADIOS constructor now has host language so bindings can change define
this at the constructor level

Separated C bindings from C glue (added) for languages using C-API (e.g.
Fortran)

bug1: when writing value characteristic bpdump requires the length before the value
bug2: fixed merging serialized collective metadata index

Continue refactoring IO, ADIOS classes

Passed ctest (MPI and nonMPI) excluding ADIOS1 engine, and Python bindings
HDF5, C bindings and C++ tests working
Introduced BeginStep EndStep functions
Renamed IO GetVariable/Attribute to InquireVariable/Attribute

Getting and defining available Variables at Open
Storing Variable position in Metadata, added to VariableBase
mpidummy: Added support for MPI_Reduce, MPI_Gatherv
Added utils and BPLS

Implemented basic buffer reading functionality
Added threading for bp serialization/deserialization
Refactored MPI functionality
Engine is now a reference
Initial Read API

Picking up config.xml from examples/heatTransfer/write/config.xml from
./build/bin/heatTransfer_write_adios2