Allow set SMTP_PORT on config

[caiquecastro]

Proposed changes

It assumes the port is 2525, but if I have a local server for development and a production SMTP server with different ports, it's needed to be configurable

Types of changes

What types of changes does your code introduce?

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• [ ] Bugfix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

• [x] I have read the CONTRIBUTING doc
• [x] Lint and unit tests pass locally with my changes
• [ ] I have added tests that prove my fix is effective or that my feature works.
• [ ] I have added necessary documentation (if appropriate)

Further comments

N/A

[coveralls]

Coverage decreased (-8.9%) to 84.211% when pulling 32cf6e22c4c452ff15385179d389cd556d1bcbf9 on caiquecastro:patch-1 into 4aef9bbdb200be41f6f4e3d429d0cd1e75e736a9 on adonisjs:develop.