[cloudflare-docs] Adding folder for PCX templates + updating contribution guidelines (#6242)

* adding content type markdown templates to github

* added link to templates folder in contributing.md

* Update static/_templates/_configuration.md

Co-authored-by: Pedro Sousa <680496+pedrosousa@users.noreply.github.com>

* Update static/_templates/_configuration.md

Co-authored-by: Pedro Sousa <680496+pedrosousa@users.noreply.github.com>

* Update static/_templates/_how-to_multi-procedure-ordered.md

Co-authored-by: Pedro Sousa <680496+pedrosousa@users.noreply.github.com>

* Update static/_templates/_reference.md

Co-authored-by: Pedro Sousa <680496+pedrosousa@users.noreply.github.com>

* Update static/_templates/_reference.md

Co-authored-by: Pedro Sousa <680496+pedrosousa@users.noreply.github.com>

* Apply suggestions from code review

Co-authored-by: Pedro Sousa <680496+pedrosousa@users.noreply.github.com>

* last edits

Co-authored-by: Pedro Sousa <680496+pedrosousa@users.noreply.github.com>