Create metric idea issue template

[divya-mohan0209]

This creates an issue template similar to the one used by the CHAOSS project for proposing a DevRel Foundation metric.

[divya-mohan0209]

Hi @j12y, thanks for pointing me to the right repo! I've added the issue template herewith and will incrementally work on other aspects of issue # 143

[arun-gupta]

@divya-mohan0209 This template is useful after we have created an initial set of metrics. Or are you suggesting that every metric that gets added here using this template?

I'm trying to strike a balance between speed and process.

[divya-mohan0209]

IMO, having a barebones template that we can iterate upon speeds up the process. Asking people to submit metrics with little to no context around the information that needs to be provided will mean we have to do a lot of back-and-forth.