Added method to delete a person on churchtools

[stollr]

As a follow up to #84 I'd like to add a method to call the API endpoint to delete a person record.

It is quite simple to use:

use CTApi\Requests\PersonRequest;

$personA = PersonRequest::find(21);
PersonRequest::delete($personA);

I haven't added documentation or unit tests, because your way of writing those is a bit hard to follow for me :-)
It would be nice if you could do that.

[stollr]

Argh... the last commit message should have been "Updated CHANGELOG"... sorry

[stollr]

Fixed by force push ^^

[DumbergerL]

@Naitsirch No Problem! I admit it's a little hard to understand. I've added the documentation.

I split it up into several commit to improve the readability:

1. create example-code in "Tests\Unit\DocsPersonRequestTest" 01a6c75
2. add Unit-Test-Method to documentation in Folder docs/src/ressources/PersonAPI.md 33e5e8e
3. generate the docs with the composer run-script docs-generator command => this will create the documentation with the code example in Folder docs/out/PersonAPI.md 7e70a52

I hope this helps!