Error parsing config default value for custom download links in main menu

[RenatoCaenaro]

evt-viewer-angular/src/assets/config/config.yaml

Line 101 in 8a171e6

url: value

"url" is not a valid absolute link so evt crash at startup.

maybe it's better to parse and validate values on the list and use only valid absolute urls and show not valid urls in the error dialog.

[RenatoCaenaro]

we could also let the user specify a local path for the link like the pdf printed edition.
so if the url start with http it's an absolute link, else it's a local link that need one other kind of validation.

[RobertoRDT]

Functioning values for "url" should be

• a valid WWW address, typically a link to a PDF file somewhere on the Internet e.g. url: https://journals.openedition.org/jtei/pdf/6511
• a path to a file in a local folder, e.g. url: assets/data/PDF/printable_version.pdf