Add aiohttp signal to modify HTTP response headers

[vicferpoy]

Related issue
closes #9253

Description

Hello team,

This PR adds a new API module to implement and manage aiohttp signals. In addition, we have implemented a new signal to modify HTTP response headers. Now, API responses do not have the Server header:

Successful

Content-Type: application/json; charset=utf-8
Strict-Transport-Security: max-age=63072000; includeSubdomains
X-Frame-Options: DENY
X-XSS-Protection: 1; mode=block
X-Content-Type-Options: nosniff
Content-Security-Policy: none
Referrer-Policy: no-referrer, strict-origin-when-cross-origin
Pragma: no-cache
Expires: 0
Cache-control: no-cache, no-store, must-revalidate, max-age=0
Content-Length: 1313
Date: Mon, 12 Jul 2021 15:11:01 GMT

Unsuccessful

Content-Type: application/problem+json; charset=utf-8
Content-Length: 71
Date: Mon, 12 Jul 2021 15:11:14 GMT

Tests performed

Unit tests

========================================= test session starts ==========================================
platform linux -- Python 3.9.5, pytest-6.2.4, py-1.10.0, pluggy-0.13.1
rootdir: /home/vicferpoy/Desktop/Git/wazuh/api
plugins: cov-2.12.0, asyncio-0.15.1
collected 238 items                                                                                    

models/test/test_model.py ............                                                           [  5%]
test/test_alogging.py ..........                                                                 [  9%]
test/test_authentication.py ..........                                                           [ 13%]
test/test_configuration.py ..........................................                            [ 31%]
test/test_util.py ...................................                                            [ 45%]
test/test_validator.py ......................................................................... [ 76%]
........................................................                                         [100%]

=================================== 238 passed, 15 warnings in 1.20s ===================================

Regards,
Víctor

[Selutario]

LGTM!