[Ubuntu] Change rebar installation to use GitHub releases (#3486)

* Change rebar installation to use gh releases

* Add source $HELPER_SCRIPTS/install.sh

* Add Erlang rebar3 to software readme

images/linux/scripts/SoftwareReport/SoftwareReport.Generator.ps1

@@ -42,6 +42,7 @@ $markdown += New-MDList -Style Unordered -Lines (@(
         (Get-ClangVersions),
         (Get-ClangFormatVersions),
         (Get-ErlangVersion),
+        (Get-ErlangRebar3Version),
         (Get-MonoVersion),
         (Get-MsbuildVersion),
         (Get-NodeVersion),