Enable putting bytes into the database via C++ and Python

[mellis13]

This PR adds the ability to put raw byte strings into the database. This PR covers the C++ and Python clients and Fortran and C clients will be addressed in a follow-up PR.

[codecov]

Codecov Report

Attention: Patch coverage is 55.76923% with 92 lines in your changes missing coverage. Please review.

Project coverage is 57.58%. Comparing base (4937fbd) to head (aae3968).
Report is 17 commits behind head on develop.

Files with missing lines	Patch %	Lines
tests/cpp/unit-tests/test_client.cpp	0.00%	42 Missing ⚠️
tests/cpp/unit-tests/test_client_prefixing.cpp	0.00%	24 Missing ⚠️
src/python/src/pyclient.cpp	0.00%	12 Missing ⚠️
src/python/bindings/bind.cpp	0.00%	6 Missing ⚠️
src/cpp/client.cpp	92.06%	5 Missing ⚠️
src/python/module/smartredis/client.py	92.85%	2 Missing ⚠️
src/python/module/smartredis/error.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           develop     #521       +/-   ##
============================================
- Coverage    95.92%   57.58%   -38.34%     
============================================
  Files           10      147      +137     
  Lines          884    11907    +11023     
  Branches         0     1138     +1138     
============================================
+ Hits           848     6857     +6009     
- Misses          36     4899     +4863     
- Partials         0      151      +151     

Files with missing lines	Coverage Δ
include/client.h	76.92% <ø> (ø)
include/redisserver.h	60.00% <ø> (ø)
src/cpp/redis.cpp	55.60% <100.00%> (ø)
src/cpp/rediscluster.cpp	66.75% <100.00%> (ø)
src/python/module/smartredis/error.py	95.45% <0.00%> (ø)
src/python/module/smartredis/client.py	97.28% <92.85%> (-0.28%)	⬇️
src/cpp/client.cpp	88.50% <92.06%> (ø)
src/python/bindings/bind.cpp	0.00% <0.00%> (ø)
src/python/src/pyclient.cpp	0.00% <0.00%> (ø)
tests/cpp/unit-tests/test_client_prefixing.cpp	0.00% <0.00%> (ø)
... and 1 more

... and 128 files with indirect coverage changes

[ashao]

Nicely done! One suggestion with regard to the unpack_bytes method in the C++ client

[ashao]

Currently this requires that the buffer and the reply from Redis are exactly the same size. This might be a little overly restrictive especially because the size of the byte string may not be known a priori. I'd suggest that we change this:

void Client::unpack_bytes(const std::string& name,
                          void* data,
                          const size_t n_buffer_size,
                          size_t* obj_size
)

The check internally should then be that the buffer size is >= to the message reply

[ashao]

Looks good. Thanks!