The proposal templates was not intended to be show for every issue,
only for proposal. Revert that issue template and add more general
one in a follow up commit.
This reverts commit 09cb38577f.
Github launched the ability to automatically populate issues and pull requests with custom templates automatically
(https://github.com/blog/2111-issue-and-pull-request-templates). This eliminates the need to have custom scripts
for populating github issues with custom templates. It should be easier for contributors to just open an issue
and not worrying about copy the template.
