Link SiennaDocs logo back to Sienna homepage

[kdayday]

Currently, the Sienna logo in the SiennaDocs subpages links back to the SiennaDocs index page, but would be good to link back to the Sienna homepage. Doesn't appear Documenter.jl has a built-in way to change the url.

• The url is defined in each .html file in the build, which is re-generated each time SiennaDocs is compiled/deployed
• Maybe a way to do this is do write a little script that search-replaces for the url, that gets run between the SiennaDocs deployment and the Sienna webpage deployment, as a third action?

Current url in .html files:
<a class="docs-logo" href="../index.html"><img src="../assets/logo.png" alt="Sienna Documentation Hub logo"/>
Desired:
<a class="docs-logo" href="https://nrel-sienna.github.io/Sienna/"><img src="../assets/logo.png" alt="Sienna Documentation Hub logo"/>