Add support for C#

[XezolesS]

Add support for C#, both .NET and Mono version of it.

Compiling C# is somewhat different than others, so I have to cook it little different.
I don't really want to break a codebase, but some methods are added to only handle C#.

The way it works is:

for .NET C#

1. Create a .NET project under the workspace folder. The project name will be .cphcsrun
2. Copy the C# source code to Program.cs in project folder.
3. Run dotnet build to compile code.
4. Run binary where located at <source_name>_bin/.cphcsrun.

for Mono C#

1. Compile the code with mcs command.
2. Run binary with mono command.

It is little bit wanky, but it works.

Also, I fixed an error that failed to delete binary after execution if there's a whitespace in the path in Windows.

I've tested every language but Haskell on Windows 10 and C, C++, C#, Python on Ubuntu 20.04 to make sure I didn't break other compilers.

[agrawal-d]

@XezolesS looks great, thanks for testing on both Linux and Windows.

1. Can you please resolve the conflicts?
2. Also, in some places, you have changed formatting even though you have not changed any code.
   Can you keep the diff limited to your code changes to minimize un-intended changes? Example package.json.

[XezolesS]

@agrawal-d Thanks for the review.
Let me know if I missed something again ;)

[agrawal-d]

Looks good, thanks!