Previously the Microsoft setup instructions did not mention supported
account types. Remark42 authenticates against the `common` endpoint by
default, which only accepts an application registered for both work or
school accounts and personal Microsoft accounts, so an application created
with any other value fails to authenticate with no hint as to why.
The reproxy manual still configured `AUTH_TWITTER_CID` and
`AUTH_TWITTER_CSEC` in its example, which have been deprecated and
non-functional since 1.14.0.
Resolves#1823.
Dmitry VerkhoturovandUmputun
29b5f88a1c