Support dots in model names

[monti-python]

Describe the bug

In our dbt project we are managing multiple schemas. We are namespacing the models with the standard SQL syntax <schema>.<relation>.sql and following this approach. It works quite well for the most part, however models with dots don't show up in the graphs on the generated docs

Steps To Reproduce

Using a model or seed with dots in their name and generating the docs (dbt docs generate && dbt docs serve) will trigger the issue.

Expected behavior

The graphs in the docs site show all relevant nodes, including those whose name contains dots.

The output of dbt --version:

installed version: 0.19.1
   latest version: 0.19.1

Up to date!

Plugins:
  - bigquery: 0.19.1
  - postgres: 0.19.1
  - redshift: 0.19.1
  - snowflake: 0.19.1

Additional context

Related to dbt-labs/dbt-core#3246

[monti-python]

Made a PR to solve it #185