Better error messages

[marcodpt]

Basically in my use of the mini ps I found 3 types of errors:

• initialization errors on the server, such as the port is busy or cryptographic key files are not accessible.

• syntax errors in the config.toml file

• errors in minijinja templates.

The first two cases require improving the server message returned directly on the command line.

In the case of template errors, these cannot be known before the request is made, and it is necessary to study the best way to return the message to the user.