7-Zip 18.06 silent native install, auto download, detection

This will:

• install 64-bit 7-Zip version on 64-bit machine
• install 32-bit 7-Zip version on 32-bit machine
• skip installation if 7-zip is persistent
• use "prepare" argument if want to only download installation files for appropriate system

This is testes on:
https://www.7-zip.org/a/7z1806-x64.exe

548ea319cbd6dda0e94d95580ad36038

731bf43ed27a3b6301eaaf3dac0f3e2e803d396c

https://www.7-zip.org/a/7z1806.exe

5cd1fbd747c118036cfe3e654979deba

fd42ffd5a2e50531431e17975e129214d580276e

To automatically download the source files additional files are needed:

Scenario:

To download source files use:

7-zip-silent-install.cmd prepare

If source files are already there, then it is possible to install with:

7-zip-silent-install.cmd

Changelog: