Since clones from the source repo running build.bat would fail to compile
and/or generate a setup file. These changes enable it to compile and to
reduce the number of error messages generated during build.

1. Added a check in build.bar to look for file named GOTIDY and if found
   it will run `go mod tidy` before each `go build`
2. Added a check for buildtools\signtool.exe and if not found displays a
   message with a URL where it can be downloaded.
3. `VersionInfoTextVersion` and `VersionInfoProductTextVersion` to nvm.iss
   to stop InnoSetup from generating a warning message about them
4. Added TODO about fixing InnoSetup message related to `PrivilegesRequired`
   See: https://stackoverflow.com/a/44575671/102699
5. Added golang.org/x/sys in go.mod for updater to get it to compile.
6. Removed the replace in go.mod for nvm that referred to author's local
   machine and updated go-fsutil require from v1.1.1 to v1.2.0
7. DID NOT FIX SignTool Error: "No certificates were found that met all
   the given criteria."