sanitize names when using them as tag value (#858)

* sanitize names when using them as tag value

related: graphite-project/graphite-web#2458

* implement updated rules

* copy tag and value validation from graphite

* better error messages

* add tests for tag validation

* Better exception messages

Co-Authored-By: Dan Cech <dan@aussiedan.com>

Co-authored-by: Dan Cech <dan@aussiedan.com>

Author: 2 people