Add tengo support to RemoteNickFormat

[42wim]

This commit add support for using the result of a tengo script in RemoteNickFormat using {TENGO}
Also adds a new toml table [tengo] with key RemoteNickFormat and value location of the script.
This also moves the TengoModifyMessage from [general] to Message in [tengo]

Documentation:

RemoteNickFormat allows you to specify the location of a tengo (https://github.com/d5/tengo/) script.
The script will have the following global variables:
to modify: result
to read: channel, bridge, gateway, protocol, nick

The result will be set in {TENGO} in the RemoteNickFormat key of every bridge where {TENGO} is specified
The script is reloaded on every message, so you can modify the script on the fly.
Example script can be found in https://github.com/42wim/matterbridge/tree/master/contrib/remotenickformat.tengo

[tengo]
RemoteNickFormat="remotenickformat.tengo"

[ghost]

Found some fixes!

P.S. share your ideas, feedbacks or issues with us at https://github.com/fixmie/feedback (this message will be removed after the beta stage).

[codeclimate]

Code Climate has analyzed commit f0d6aa1 and detected 0 issues on this pull request.

The test coverage on the diff in this pull request is 0.0% (50% is the threshold).

This pull request will bring the total coverage in the repository to 10.4% (-0.2% change).

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