change default scope to 'apitestsuite'

[DougReeder]

https://github.com/remotestorage/spec/blob/main/release/draft-dejong-remotestorage-24.txt, in section "9. Bearer tokens and access control", says
These access
scopes are represented as strings of the form ,
where the string SHOULD be lower-case alphanumerical, other
than the reserved word 'public', and can be ':r' or ':rw'.

So it appears that dashes are not a legal part of scope names

[raucao]

I wasn't even aware of that, and am also using dashes for some cases, because they're much more readable. I think this should be fixed in the spec instead.

[DougReeder]

I guess it says, should rather than must, but, yes, we should nail this down in the spec.