Add reference to the GitHub repository/issues

[creharmony]

As user, I would like to know where the project is hosted.

support point of view:

• to report a bug
• to report a improvment

help point of view

• to access project's readme

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this could help end users and make some ads for this repo

suggest to add link either on home page and/or on top level menu once logged

[SamuelTallet]

Good idea!