Fix links in Javadoc and reference docs

- Fix broken links (by using a new URL, an alternative URL, or a
  Wayback Machine link)

- Use HTTPS where possible

- Remove https://issuetracker.springsource.com/browse/EBR-349: this
  link is dead and is also mentioned in
  https://jira.spring.io/browse/SPR-8093

- Clean up nohttp allowlist.lines

Closes gh-28876

gradle/docs.gradle

@@ -153,7 +153,7 @@ asciidoctorPdf {
 task docsZip(type: Zip, dependsOn: ['api', 'asciidoctor', 'asciidoctorPdf', 'dokkaHtmlMultiModule']) {
 	group = "Distribution"
 	description = "Builds -${archiveClassifier} archive containing api and reference " +
-			"for deployment at https://docs.spring.io/spring-framework/docs."
+			"for deployment at https://docs.spring.io/spring-framework/docs/."
 
 	archiveBaseName.set("spring-framework")
 	archiveClassifier.set("docs")