keymgr: Allow periods in ArtiPath and ArtiPathComponent.
The HsId
of an onion service is included in the ArtiPath of
client auth keys, and an HsId
contains a .onion
component. Let's
allow .
for now. In the future, we may want to update the code (and
keystore structure) to strip away the .onion
part before building the
ArtiPath
.