The new app / lib templates should help prevent checking in msbuild binlog files

[jonthysell]

Summary

1. The init-windows for the new templates should inject *.binlog into the project root .gitignore if the ignore file exists (and the line doesn't exist)
2. (Optional): We shouldn't dump the binlog to the root folder, maybe we could put it somewhere else (maybe the windows folder, where it's easier for us to gitignore it) and then output the path to the log file at the end of the command.

Motivation

Right now, if you run run-windows --logging you'll get an msbuild.binlog file in the root of your project file (where you run run-windows 99% of the time). This file risks being checked in accidentally.

Basic Example

No response

Open Questions

No response

[chrisglein]

Related: #5937
Issue there was the binlog getting dropped in the root and having different rules for what the gitignore could do. Moving where it got dropped would help.