Align Hello.sv with the documentation.

[niko-vcc]

Documentation at https://melt.cs.umn.edu/silver/install-guide/#testing-things-out-by-building-the-tutorials claims that the World is upper case (as is expected in most hello-world applications).

Changes

1. Minor update on a string to align the output of the Hello.sv with the online documentation
2. Simplified the install script. Removed redundant calls to readlink, and the code that was required to maintain different executions per platform. Now the code only depends on a bash-ism.

Documentation

• Align website documentation and source code, by updating the source code to align with existing documentation (and common casing in Hello World)

Testing

Locally, this change affects my silver docker build where I validate that the image is correctly built and things are as expected by utilizing the Hello.sv and expecting the output.
Same docker build process, also is using the install script.

Dependencies

To print the $REPO a new runtime dependency is added to git - expectation is that git is already available. If this is undesired, printing the root, could be removed anyway.

Assumptions

That the install script and the scripts to be installed live in the same directory (same as before).

Quality

There are two shellcheck warnings that exist in code I didn't touch, newly added/modified code is shellcheck warning free

$ shellcheck install-silver-bin 

In install-silver-bin line 6:
  echo "~/bin not found. Aborting."
        ^------------------------^ SC2088 (warning): Tilde does not expand in quotes. Use $HOME.


In install-silver-bin line 7:
  case `uname` in
       ^-----^ SC2006 (style): Use $(...) notation instead of legacy backticks `...`.

Did you mean:
  case $(uname) in

For more information:
  https://www.shellcheck.net/wiki/SC2088 -- Tilde does not expand in quotes. ...
  https://www.shellcheck.net/wiki/SC2006 -- Use $(...) notation instead of le...