This adds API tokens as a new credential type. Their format is:
`oh.<name>.<random chars>`

The "oh." prefix is used to tell them apart from a JWT access token,
because they're both used as a Bearer authorization scheme, but there
is no semantic value attached to any of the other parts.

They are stored hashed in the user's profile, and can be listed, added
or removed managed with the new `openhab:users` console command.

Currently the scopes are still not checked, but ultimately they could
be, for instance a scope of e.g. `user admin.items` would mean that the
API token can be used to perform user operations like retrieving info
or sending a command, _and_ managing the items, but nothing else -
even if the user has more permissions because of their role (which
will of course still be checked).

Tokens are normally passed in the Authorization header with the Bearer
scheme, or the X-OPENHAB-TOKEN header, like access tokens.
As a special exception, API tokens can also be used with the Basic
authorization scheme, **even if the allowBasicAuth** option is not
enabled in the "API Security" service, because there's no additional
security risk in allowing that. In that case, the token should be
passed as the username and the password MUST be empty.

In short, this means that all these curl commands will work:
- `curl -H 'Authorization: Bearer <token>' http://localhost:8080/rest/inbox`
- `curl -H 'X-OPENHAB-TOKEN: <token>' http://localhost:8080/rest/inbox`
- `curl -u '<token>[:]' http://localhost:8080/rest/inbox`
- `curl http://<token>@localhost:8080/rest/inbox`

2 REST API operations were adding to the AuthResource, to allow
authenticated users to list their tokens or remove (revoke) one.
Self-service for creating a token or changing the password is more
sensitive so these should be handled with a servlet and pages devoid
of any JavaScript instead of REST API calls, therefore for now they'll
have to be done with the console.

This also fixes regressions introduced with openhab#1713 - the operations
annotated with @RolesAllowed({ Role.USER }) only were not authorized
for administrators anymore.

Signed-off-by: Yannick Schaus <github@schaus.net>

Reusing the password salt is bad practice, and changing the
password changes the salt as well which makes all tokens
invalid.

Put the salt in the same field as the hash (concatenated
with a separator) to avoid modifying the JSON DB schema.

Signed-off-by: Yannick Schaus <github@schaus.net>

The X-OPENHAB-TOKEN header now has priority over the Authorization
header to credentials, if both are set.

Signed-off-by: Yannick Schaus <github@schaus.net>

Signed-off-by: Yannick Schaus <github@schaus.net>

Signed-off-by: Yannick Schaus <github@schaus.net>

Signed-off-by: Yannick Schaus <github@schaus.net>

Signed-off-by: Yannick Schaus <github@schaus.net>

Signed-off-by: Yannick Schaus <github@schaus.net>

Signed-off-by: Yannick Schaus <github@schaus.net>

Signed-off-by: Yannick Schaus <github@schaus.net>

Signed-off-by: Yannick Schaus <github@schaus.net>

Signed-off-by: Yannick Schaus <github@schaus.net>