add templates for new Issue and Pull Requests

[wrathdev]

I think we need templates for Issues and PRs, that will make PRs and issues consistent.

https://docs.github.com/en/free-pro-team@latest/github/building-a-strong-community/creating-a-pull-request-template-for-your-repository

[Dutta-SD]

If this is available, I would like to work on it.

[tarishij17]

issue template: #19
pr template: #18

[tarishij17]

@wrathdev can you please confirm whether the PR looks good or need updations?