Link connector docs in the Add Source dialog

The access review Add Source dialog listed each connector with no
path to its setup documentation. Connectors that have a published
docs page on probo.com now surface a "Documentation" link on the
card, opening the page in a new tab; connectors without a page show
nothing extra.

The link is data-driven from the connector registry: a new
DocumentationURL on the provider Registration, populated for the 12
documented providers via a single accessReviewDocsURL helper, is
surfaced as a nullable documentationUrl on ConnectorProviderInfo and
rendered by the console only when present. This keeps the registry
the single source of truth and adds no client-side provider map.

The links resolve once the probo.com access-review docs pages are
deployed; until then they 404, so deploy the docs alongside this
change.

Signed-off-by: Aurélien Sibiril <81782+aureliensibiril@users.noreply.github.com>

pkg/connector/provider/railway.go

@@ -31,9 +31,10 @@ import (
 
 func railwayRegistration() *Registration {
 	return &Registration{
-		Provider:       coredata.ConnectorProviderRailway,
-		DisplayName:    "Railway",
-		SupportsAPIKey: true,
+		Provider:         coredata.ConnectorProviderRailway,
+		DisplayName:      "Railway",
+		DocumentationURL: accessReviewDocsURL("railway"),
+		SupportsAPIKey:   true,
 		// Railway authenticates with an account API token as Authorization:
 		// Bearer. A single GraphQL call resolves the account's workspaces and
 		// their members, so there is nothing to pick (Pattern 3). Railway