[php-slim4] Add lazy CORS implementation

[ybelenko]

Core team Slim member recommends to apply CORS headers via custom response emitter to also catch any exceptions.
Ref: slimphp/Slim#2999 (comment)

Closes #6851

Of course I've checked it locally:

* Preparing request to http://phpslim4.test/v2/pet/5
* Current time is 2022-03-22T18:24:37.435Z
* Using libcurl/7.69.1 OpenSSL/1.1.1g zlib/1.2.11 brotli/1.0.7 libidn2/2.1.1 libssh2/1.9.0 nghttp2/1.41.0
* Using default HTTP version
* Enable timeout of 1000000ms
* Enable automatic URL encoding
* Enable SSL validation
* Enable cookie sending with jar of 0 cookies
* Hostname phpslim4.test was found in DNS cache
*   Trying 127.0.0.1:80...
* Connected to phpslim4.test (127.0.0.1) port 80 (#27)

> OPTIONS /v2/pet/5 HTTP/1.1
> Host: phpslim4.test
> User-Agent: insomnia/2020.4.0
> Access-Control-Request-Method: DELETE
> Access-Control-Request-Headers: Content-Type,X-PINGOTHER
> Origin: http://localhost
> Accept: */*

* Mark bundle as not supporting multiuse

< HTTP/1.1 200 OK
< Date: Tue, 22 Mar 2022 18:24:37 GMT
< Server: Apache/2.4.46 (Unix) PHP/7.4.22
< X-Powered-By: PHP/7.4.22
< Access-Control-Allow-Origin: http://localhost
< Access-Control-Allow-Credentials: true
< Vary: Origin
< Access-Control-Allow-Methods: GET, POST, PUT, PATCH, DELETE
< Access-Control-Allow-Headers: authorization, content-type, x-requested-with
< Transfer-Encoding: chunked
< Content-Type: text/html; charset=UTF-8


* Received 5 B chunk
* Connection #27 to host phpslim4.test left intact

cc @jebentier, @dkarlovi, @mandrean, @jfastnacht, @renepardon

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