Add proposal answer templates (#41)

* Add Proposal Answer Template basic functionality

* Apply pagination, add functionality for copy + delete

* Add Answer Template to Proposal

* Linting decidim-templates

* Add more tests

* Linting

* Fix class name

* Add latest review changes

* Implement code review recommendations

* Add corect labels to table header

* Running EsLint

* Running ERBLinter

Co-authored-by: Alexandru-Emil Lupu <[email protected]>