Integrating remoting 2.53.2

[FIX SECURITY-234] Abort plugin/core update on checksum mismatch

This is the logical consequence of what we agreed in the CERT meeting
today, given that the 2.53.2 is public.

(cherry picked from commit d2e0f6fa)

[FIX SECURITY-233] Remove multipart form exception from crumb filter

[FIX SECURITY-225] Add RequirePOST annotations

[FIX SECURITY-95] Add CSP headers to files served by Jenkins

[FIXED JENKINS-31718] Integrated a new version of Remoting with a fix for a regression in concurrent socket connections.

(cherry picked from commit e6d8500d)

In the project meeting today we decided to pull this in.

- The previous check was to narrow.
- We now check on AccessControlled (which is implemented by Item)
- We now also check on Permission.READ (which is the generic read permission)

This should allow subtasks who's task may not be an Item to at least implement AccessControlled to alow visibility.

There remains an open question as to whether tasks that are not AccessControlled should ever be visible in the UI

(cherry picked from commit cf1fdf98)

(cherry picked from commit aec2d8af)

(cherry picked from commit 7fdb5891)

(cherry picked from commit 04a874ac)

[SECURITY-218] - Functional tests for CLI

[SECURITY-218] Blackbox test