feat: add always_bcc feature

[mstenz]

Creating a Pull Request

Description of the change

Allows the always_bcc feature to be configured, this allows some type of MIRRORING all emails that are sent through the server

Motivation and Context

we need this feature in our environment to debug applications that send out emails

How Has This Been Tested?

this is a very easy change. that used a copy of different settings as a skeleton. tested this on a live running container by setting the variable

Types of Changes

• [x] New feature (non-breaking change which adds functionality)
• [x] Documentation (adding or updating documentation)

Checklist:

• [x] My change requires a change to the documentation and I have updated the documentation accordingly.
• [x] My change adds a new configuration variable and I have updated the .env.example file accordingly.

[mstenz]

@juanluisbaptiste can you please check this PR, it is very important to us

[mstenz]

@juanluisbaptiste I just have seen you spend some time on this project today, can you please also merge this request? Thank you.