Allow arbitrary folders to be synchronized

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Currently the nextCloud app will create a one to one folder representation of the remote server when synchronizing a directory. However it would be really helpful on a mobile device to map a device directory to a remote server directory.

A use case would be syncronizing a workspace directory of an app on the mobile device with a dedicated directory path on the remote server. For instance a directory with pictures often edited by a mobile app synchronized with a subpath of 'Photos' on the remote server. Or you want to synchronize a shared folder with music into your music library directory on your mobile device...

This would assume issue #19 to be working, such that changes on the mobile device are propagated to the remote server.

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Inizia esaminando l’issue #19, che questa funzionalità presuppone sia funzionante, quindi traccia il modo in cui l’app Android associa attualmente le cartelle locali e remote durante la sincronizzazione. Definisci come una directory del dispositivo viene associata a un sottopercorso remoto, incluse le cartelle condivise e le modifiche bidirezionali. Il lavoro è completato quando le associazioni arbitrarie tra cartelle locali e remote si sincronizzano in modo affidabile in entrambe le direzioni.

Scritto dal modello di indicizzazione a partire dal testo della issue.