ci: align repo automation with the new label set

Apply needs-triage to new bug and feature issues from the templates.
Drop the retired npm label from the Dependabot npm updates.
Give Docker, Dockerfile, and compose paths their own docker label
instead of folding them into ci.

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -1,7 +1,7 @@
 name: Bug Report
 description: Report a bug in BookOrbit
 title: "[Bug] "
-labels: ["bug"]
+labels: ["bug", "needs-triage"]
 body:
   - type: textarea
     id: description

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -1,7 +1,7 @@
 name: Feature Request
 description: Suggest a new feature or improvement for BookOrbit
 title: "[Feature] "
-labels: ["feature"]
+labels: ["feature", "needs-triage"]
 body:
   - type: textarea
     id: description