fix: spring security http headers configuration

[RadovanTomik]

Negotiator pull request:

Description:

Adds default configurations for csfr and cors headers.

Checklist:

Make sure you tick all the boxes bellow if they are true or do not apply:

• [x] I have performed a self review of my code
• [x] My code follows Google Java Code style
• [x] I have made my code as simple as possible
• [x] I have added unit tests and the code coverage has not decreased
• [x] I have updated the documentation in all relevant places

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 66.66667% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 78.50%. Comparing base (e5e25f8) to head (ea0770a).

Files	Patch %	Lines
...or/configuration/security/OAuthSecurityConfig.java	66.66%	0 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #255 +/- ## ============================================ - Coverage 78.54% 78.50% -0.04% + Complexity 895 894 -1 ============================================ Files 122 122 Lines 2740 2740 Branches 154 155 +1 ============================================ - Hits 2152 2151 -1 Misses 490 490 - Partials 98 99 +1 ``` | [Flag](https://app.codecov.io/gh/BBMRI-ERIC/negotiator/pull/255/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=BBMRI-ERIC) | Coverage Δ | | |---|---|---| | [unit](https://app.codecov.io/gh/BBMRI-ERIC/negotiator/pull/255/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=BBMRI-ERIC) | `78.50% <66.66%> (-0.04%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=BBMRI-ERIC#carryforward-flags-in-the-pull-request-comment) to find out more.

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