Make Issue template for this repo

[dataders]

make a template that at minimum requires that users share:

• their dbt-sqlserver version,
• the database product they are using (e.g. SQL Server 2012, Azure SQL)
• the relevant excerpt of their log/dbt.log

[sdebruyn]

Same for PRs while someone is looking at it anyway

[joshmarkovic]

@sdebruyn, this is great idea! Is this something you'd like to work on?