wip: Generalize authorize function, add file and role operations

[naugtur]

• changed the authorization function to accept anything and pass it to sp-auth to handle all methods supported.
• added functions for getting the file metadata and content as stream
• added functions for role management (not sure what they do, I'm figuring these calls out)
• minor refactor of input checking

Any tips from people who know sharepoint would help.
I need to set single file permissions to single users and have no idea how to proceed yet :)

[naugtur]

I removed all new before Error because it doesn't do anything in Javascript really other than creating an unnecessary object in memory maybe.

[naugtur]

Hi,

I needed much more features related to sharing and permissions, so I switched to pnpjs.
I no longer have the ability to finish this contribution in my working hours.

Feel free to merge just parts of it. I'd recommend removing the roles functionality and merging the rest if you don't want to continue the work on roles.

[jezhiggins]

No worries 👍 Thanks for your work.