Add a fetch refspec to fetch tags from a Radicle remote. The
`--no-tag` option is also included. This is to ensure that it is easy
to collaborate by having tags placed in the remote namespace of
another peer. However, if the namespace is the default `rad` remote,
then tags are expected to be allowed -- this is to pave way for the
feature of canonical tags.
In the tests, the `--tags` option is removed -- and is generally
recommended that it is not used. This is to ensure that it does not
override the `--no-tag` option.