We replaced the jwtauth and jwx libraries with a minimal custom wrapper
around go-jose because we don’t need the full feature set provided by jwx.
Implementing our own wrapper simplifies the codebase and improves
maintainability.
Moreover, go-jose depends only on the standard library, resulting in a
leaner dependency that still meets all our requirements.
This change also reduces the SFTPGo binary size by approximately 1MB
Signed-off-by: Nicola Murino <nicola.murino@gmail.com>