Annotations and PHPDoc Tags (PRS-5) and support

This is a big plan, it is unlikely to be implemented immediately.

refs #473

The format written in DocComment includes "tag" defined from phpDocumentor, "annotation"defined from Doctorine, PSR-5 style tag and Phan's array-shepes.

For these support we need to rewrite the PHPDoc parser and we do not have a schedule to implement it immediately.

## Definitions

* in English
* [PHPDoc tags and annotations · emacs-php/emacs-for-php Wiki](https://github.com/emacs-php/emacs-for-php/wiki/PHPDoc-tags-and-annotations)
* in Japanese
* [PHPDoc tags and annotations · emacs-jp/php-info Wiki](https://github.com/emacs-jp/php-info/wiki/PHPDoc-tags-and-annotations)
* [2018年のPHPDoc事情とPSR-5 - Qiita](https://qiita.com/tadsan/items/72b02339d12120ca37d7)

## Currently status

- [x] Basic PHPDoc Tag support
- [x] Basic Doctrine Annotation support (without recursive)
- [ ] Complex Doctrine Annotation support (including recursion)
- [ ] PSR-5 style type notation
- [ ] Phan's array-shapes notation
- [ ] PHPStan's intersection types