Add Issue and PR templates

[wbnns]

This PR adds Issue and PR templates to the repository to help organize the way issues and pull requests are opened, by standardizing the type of information that gets submitted.

I pulled these over from the Coinbase Wallet SDK; they're the same ones that are being used there, except refactored for Base. You can play with opening an issue over there to get an idea of what it looks like. Note: I dropped the smartphone-related info from them before adding to this repo since it's not going to be relevant for the purposes of running a node.

When/if #15 is incorporated I would also follow-on to update this in the future to ask users to include a version when opening an issue. I left this section out for now since there is no versioning at present in the repo.

[mdehoog]

Thanks for the contribution. I think for now we'll keep this PR open to see what types of issues folks report so we can get a better understanding of a good set of form inputs, rather than copying directly from the Wallet SDK, which I think has a slightly different audience.

[wbnns]

@mdehoog

Ok, copy, thanks for the review!

[wbnns]

Since it has been some time going to go ahead and close this. Not sure we need it but happy to bring back/reopen if requested or circumstances change. 👍