[portal] Create "dictionary" of terms in the provider portal

[rhinodavid]

Add a section to the (non-existent) "About" page on the portal which defines terms used in the portal. I'm specifically thinking about "Service Provider" at the moment, but we could also define "Admin", "Super Admin", and new terms as the project expands ("Community Champion").

My idea for this is to commit the definitions to source control instead of creating a database record. It could just be a json file like

[{
   term: "Service Provider",
   definition: "<maybe some markdown?>"
}]

Then the Sapper App should parse it to make a section of the site.

Note: I DO NOT think we should need one of these for the client. Everything there should be clear enough to understand without reading a dictionary.

[jacobvenable]

@rhinodavid What is the intent of these definitions? Do you foresee our providers needing these definitions to understand the provider portal? Could this be mitigated via research in #395 and other pages of the portal?