[WIP] Added More Phpdoc Fixers

TODO:
* [x] Added phpdoc_seperation
* [x] Fix the behaviour with some annotations like the phpunit ones - introduced a tag class
* [x] Refactor the docblock classes to model the situation more clearly
* [x] Add tests for the `Tag` class
* [x] Add tests for the `DocBlock` class
* [x] Added phpdoc_order
* [x] Perform regression testing on league/flysystem
* [x] Based on results from testing, make improvements
* [x] Add phpdoc_var fixer
* [x] Perform regression testing on symfony/symfony
* [x] Based on results from testing, make improvements, add more test cases
* [x] Move the phpdoc_order fixer to contrib level
* [x] Add a phpdoc_trim fixer at symfony level, partly taken from phpdoc_separation
* [x] Added phpdoc_no_return_void
* [x] Review fixer orders
* [x] Perform regression testing on guzzle/guzzle
* [x] `@see`, `@link`, `@deprecated`, `@since`, `@author`, `@copyright`, and `@license` annotations should be kept together rather than forced apart by the separation fixer
* [x] Support annotations with descriptions including bank lines
* [x] Perform regression testing on doctrine/common
* [x] Perform regression testing on guzzle/guzzle and symfony/symfony again
* [x] Fix more bugs, and add more test cases
* [x] Perform regression testing on flysystem guzzle, doctrine, symfony again
* [x] Analyse current code coverage and cleanup code
* [x] Add tests for the `TagComparator`
* [x] Add missing `DocBlock` class tests
* [x] Add tests for the `Line` class
* [x] Add tests for the `Annotation` class
* [x] Test on dingo/api, factory-muffin, aws sdk v2 and v3
* [x] Discuss fixer names
* [x] Add fixers to change var to type and type to var
* [ ] Document why the fixer orders are as they are
* [ ] Request another review by @keradus
* [ ] Apply changes
* [ ] Find more php repos to test these fixers on
* [ ] Further reviews?

why a nowdoc instead of simply `'<?php ...'` ?