Create An Issue Template for Akka.persistence.linq2db

[to11mtm]

We should provide an issue template to make it easier for users to provide the right information to help them. Here's a draft I put together:

When Filing an issue, please provide as much of this information as possible:

• What Database you are using (e.g. "MS SQL Server 2014", or "PostgreSQL 8.3")
• Your version of Akka.NET
• Your version of Akka.Persistence.Linq2db
• Your version of Linq2Db installed (especially if it is different from what is bundled!)
• Whether you are on .NET Framework, Core, and which version of such.
• As much of your configuration as possible, For security reasons, please do not include any passwords, and please do not use real server names.