add php-parser

* [ ] add gadget
* [ ] test: `@todo`
* [ ] test: var_dump
* [ ] test: die
* [ ] test: `// dont commit`

more complex ideas

* [ ] blacklist of functions that are not allowed
* [ ] blacklist of comments that trigger issues
* [ ] issue severity should be configurable per blacklist comment/function

Question: how to escalate on `goto` :smile: