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

src/docs/asciidoc/web/webflux-view.adoc

@@ -26,7 +26,7 @@ configuration involves a few bean declarations, such as
 `SpringResourceTemplateResolver`, `SpringWebFluxTemplateEngine`, and
 `ThymeleafReactiveViewResolver`. For more details, see
 https://www.thymeleaf.org/documentation.html[Thymeleaf+Spring] and the WebFlux integration
-http://forum.thymeleaf.org/Thymeleaf-3-0-8-JUST-PUBLISHED-td4030687.html[announcement].
+https://web.archive.org/web/20210623051330/http%3A//forum.thymeleaf.org/Thymeleaf-3-0-8-JUST-PUBLISHED-td4030687.html[announcement].
 
 
 

src/docs/asciidoc/web/webflux.adoc

@@ -34,7 +34,7 @@ The other part of the answer is functional programming. Much as the addition of
 in Java 5 created opportunities (such as annotated REST controllers or unit tests), the addition
 of lambda expressions in Java 8 created opportunities for functional APIs in Java.
 This is a boon for non-blocking applications and continuation-style APIs (as popularized
-by `CompletableFuture` and http://reactivex.io/[ReactiveX]) that allow declarative
+by `CompletableFuture` and https://reactivex.io/[ReactiveX]) that allow declarative
 composition of asynchronous logic. At the programming-model level, Java 8 enabled Spring
 WebFlux to offer functional web endpoints alongside annotated controllers.
 
@@ -87,7 +87,7 @@ Spring WebFlux. It provides the
 https://projectreactor.io/docs/core/release/api/reactor/core/publisher/Mono.html[`Mono`] and
 https://projectreactor.io/docs/core/release/api/reactor/core/publisher/Flux.html[`Flux`] API types
 to work on data sequences of 0..1 (`Mono`) and 0..N (`Flux`) through a rich set of operators aligned with the
-ReactiveX http://reactivex.io/documentation/operators.html[vocabulary of operators].
+ReactiveX https://reactivex.io/documentation/operators.html[vocabulary of operators].
 Reactor is a Reactive Streams library and, therefore, all of its operators support non-blocking back pressure.
 Reactor has a strong focus on server-side Java. It is developed in close collaboration
 with Spring.

src/docs/asciidoc/web/webmvc-view.adoc

@@ -479,7 +479,7 @@ In similar fashion, you can specify HTML escaping per field, as the following ex
 [[mvc-view-groovymarkup]]
 == Groovy Markup
 
-The http://groovy-lang.org/templating.html#_the_markuptemplateengine[Groovy Markup Template Engine]
+The https://groovy-lang.org/templating.html#_the_markuptemplateengine[Groovy Markup Template Engine]
 is primarily aimed at generating XML-like markup (XML, XHTML, HTML5, and others), but you can
 use it to generate any text-based content. The Spring Framework has a built-in
 integration for using Spring MVC with Groovy Markup.

src/docs/asciidoc/web/websocket.adoc

@@ -597,7 +597,7 @@ a key reason for having SockJS. This section covers important
 considerations about running in those browsers.
 
 The SockJS client supports Ajax/XHR streaming in IE 8 and 9 by using Microsoft's
-https://blogs.msdn.com/b/ieinternals/archive/2010/05/13/xdomainrequest-restrictions-limitations-and-workarounds.aspx[`XDomainRequest`].
+https://web.archive.org/web/20160219230343/https://blogs.msdn.com/b/ieinternals/archive/2010/05/13/xdomainrequest-restrictions-limitations-and-workarounds.aspx[`XDomainRequest`].
 That works across domains but does not support sending cookies.
 Cookies are often essential for Java applications.
 However, since the SockJS client can be used with many server