feat: default bcc

[rubnogueira]

Q	A
Bug fix? (use the a.b branch)	No
New feature/enhancement? (use the a.x branch)	Yes
Deprecations?	No
BC breaks? (use the c.x branch)	No
Automated tests included?	No
Related user documentation PR URL	mautic/documentation#314
Related developer documentation PR URL	NA
Issue(s) addressed	NA

Description:

This PR was based on the #7681 made by @regevbr and it's rebased with the 5.x branch.

Add the ability to set a default BCC, so any mail that was not set with one, will get the default one (if set).
1 use case is to save all outgoing emails in a different email account for debugging and history preservation - with this feature it is much easier to achieve without changing 100's of email configurations

Steps to test this PR:

1. Load up
2. Set a default BCC address in the email configuration section
3. Send out a test email and make sure it was sent to the bcc address as well. ( you will need to configure the email settings to something that will actually send out emails)
4. Create an email template, and set a different bcc email to it
5. Get the email to be sent out (in a flow) and make sure that it was bcc'd to the email-specific address and not the default one

[RCheesley]

Thanks for the PR @rubnogueira - welcome to the community!

We will need to move the documentation PR over to https://github.com/mautic/user-documentation as we are deprecating the old repo - are you able to do that?

Hope that we can get some reviews tomorrow during Open Source Friday!

[RCheesley]

@all-contributors please add @rubnogueira for code

[allcontributors]

@RCheesley

I've put up a pull request to add @rubnogueira! 🎉

[codecov]

Codecov Report

Merging #12669 (a827ac8) into 5.x (e4370ae) will increase coverage by 0.00%.
The diff coverage is 92.85%.

@@            Coverage Diff            @@
##                5.x   #12669   +/-   ##
=========================================
  Coverage     58.66%   58.67%           
- Complexity    33626    33631    +5     
=========================================
  Files          2181     2181           
  Lines        101816   101829   +13     
=========================================
+ Hits          59734    59746   +12     
- Misses        42082    42083    +1     

Files	Coverage Δ
app/bundles/EmailBundle/Form/Type/ConfigType.php	100.00% <100.00%> (ø)
app/bundles/EmailBundle/Helper/MailHelper.php	67.15% <90.90%> (+0.30%)	⬆️

[regevbr]

@rubnogueira thanks for taking care of this. Please notice that one of the CI steps have failed with something you can easily fix :-)

[RCheesley]

Hi @rubnogueira are you able to address the PHPSTAN failure please? Let us know if you need any assistance!