Move json.hpp to a peer folder of other third-party dependencies - Stage 1

[Matthew Koscumb (mkoscumb)]

Beyond being good dependency hygiene, this will also allow adopters which have their own copy of json.hpp to more easily use that when integrating the 1DS C++ SDK (via include path modification)

This work will be broken down into three PRs.

1. #This PR# Copy json.hpp from lib\include\mat => nlohmann\ update include paths accordingly.
2. Update include paths in the private modules repo.
3. Remove lib\include\mat\json.hpp and update the private modules repo commit to the result of Stage 2.

[Tom Tan (ThomsonTan)]

The new json.hpp file seems cannot be loaded into github for review because it has too much lines.

Can we download this json.hpp file from github during build instead of copying it?

[Lalit Kumar Bhasin (lalitb)]

Unfortunately, macOS build is still not working, it's on me. Hopefully, this doesn't break it. We should be able to force-merge it for now.

[Lalit Kumar Bhasin (lalitb)]

The new json.hpp file seems cannot be loaded into github for review because it has too much lines.
Can we download this json.hpp file from github during build instead of copying it?

Tom Tan (@ThomsonTan) - It's actually copied from lib/mat directory to new location, so content needn't be reviewed. Because of 3 step process, it can't be moved from lib/mat to root directory. I think downloading from Github can be tracked separately.

[Tom Tan (ThomsonTan)]

The new json.hpp file seems cannot be loaded into github for review because it has too much lines.
Can we download this json.hpp file from github during build instead of copying it?

Tom Tan (@ThomsonTan) - It's actually copied from lib/mat directory to new location, so content needn't be reviewed. Because of 3 step process, it can't be moved from lib/mat to root directory. I think downloading from Github can be tracked separately.

Ok, comparing large files is not very intuitive in the revie UI, but I've verified the file move.

[Tom Tan (ThomsonTan)]