chore(): migrate to github issue forms

[micalevisk]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[x] Other... Please describe:

Just because GitHub issue forms look nicer than issue templates, and also to enforce some standard across issues in this repo.

What is the new behavior?

See them in action here: https://github.com/micalevisk/typeorm/issues/new/choose

Pretty much the same as others @nestjs repos, with minor changes:

• https://github.com/nestjs/mapped-types
• https://github.com/nestjs/terminus

Does this PR introduce a breaking change?

[ ] Yes
[x] No

[kamilmysliwiec]

LGTM