Add SMTP CONFIG options to Config Panel

[ericgeldmacher]

Problem

• Adding SMTP config options to config panel

Solution

• Made nessarry changes to config_panel.toml and conf/config.yml

PR Status

• [x] Code finished and ready to be reviewed/tested
• [x] The fix/enhancement were manually tested (if applicable)

Automatic tests

Automatic tests can be triggered on https://ci-apps-dev.yunohost.org/ after creating the PR, by commenting "!testme", "!gogogadgetoci" or "By the power of systemd, I invoke The Great App CI to test this Pull Request!". (N.B. : for this to work you need to be a member of the Yunohost-Apps organization)

[OniriCorpe]

Oh thank you! I was planning to do this in the next few days ^w^

[ericgeldmacher]

ask.fr and help.fr values in config_panel.toml for these settings were generated with google translate. My apologies if they are not correct.