funding: add .well-known/funding-manifest-urls file and URL

See https://floss.fund/funding-manifest/ and https://en.wikipedia.org/wiki/Well-known_URI

This link back to MeB.org funding.json can be accessed two ways:
1. In the github repo, for use with repositoryUrl.wellKnown using "https://github.com/metabrainz/bookbrainz-site/blob/main/.well-known/funding-manifest-urls"
2. for use with webpageUrl.wellKnown, should point to the new path "https://bookbrainz.org/.well-known/funding-manifest-urls"

.well-known/funding-manifest-urls

@@ -0,0 +1 @@
+https://metabrainz.org/funding.json

src/server/app.js

@@ -89,6 +89,7 @@ else {
 	app.use(serveStatic(path.join(rootDir, 'static/js')));
 }
 app.use(express.static(path.join(rootDir, 'static')));
+app.use('/.well-known', express.static(path.join(rootDir, '.well-known')));
 
 app.use(session(process.env.NODE_ENV));