[WebUI] Fix config ID

[Minor] Update github issue template

[WebUI] Add summary to the Throughput tab

[WebUI] Initial clusters support

Example of usage:

~~~lua
rspamd_plugins.multimap = {
  webui = {
    test = {
      handler = function(task, conn)
        conn:send_ucl({success = true})
      end
    }
  }
}

[Feature] New URL filters in multimap

MFH: true

* [CritFix] Deal with absent headers in DKIM
* [CritFix] Do not trust remote shingles count
* [CritFix] Fix headers selection in DKIM verification
* [Feature] Add EXT_CSS rule
* [Feature] Add toggle for disabling SURBLs
* [Feature] Extend redis lock when learning spawned
* [Feature] Parse <link> HTML tags
* [Fix] Avoid reusing g_error (Fixes #1262)
* [Fix] Do not reset loaded ANN when learning is requested
* [Fix] Fix another issue with external deps in SA
* [Fix] Fix body trie matching
* [Fix] Fix checking of DKIM bodies that needs just `\n` to be added
* [Fix] Fix fuzzy hashes count
* [Fix] Fix keys names
* [Fix] Fix length calculations for url encoded urls
* [Fix] Fix matching of the same patterns from different tries
* [Fix] Fix name of var
* [Fix] Fix parsing of URLs with spaces and other bad chars
* [Fix] Fix probability calculations for fuzzy redis backend
* [Fix] Fix signing headers creation in DKIM
* [Fix] Plug memory leak
* [Fix] Really fix chained SA dependencies
* [Fix] Really increase lock lifetime
* [Fix] Use checksum to avoid intersection between different ANNs
* [Fix] Use rspamd hashes in embedded ucl
* [Fix] Yet another change for testing external deps

Signed-off-by: Vsevolod Stakhov <vsevolod@highsecure.ru>

[Minor] Update `mid` list

Fix shm on DragonFly

Rspamd tried to call shm_open(3) with a path in the root filesystem
(e.g. /rhm.3f0fd440d46fac91e1b4). But DragonFly uses regular files
for shm. Obviously, this fails, because rspamd has no permissions
to create files in the root (/).

Lots of lines like the following were found in
/var/log/rspamd/rspamd.log before this patch:

    rspamd_shmem_mkstemp: /usr/obj/dports/mail/rspamd/rspamd-1.4.1/src
      /libutil/util.c:1970: failed to create temp shmem
      /rhm.3f0fd440d46fac91e1b4: Permission denied

Also, rspamd made the receiving of mail very slow, when used
in the pre-accept rmilter setting, due to these errors. Even
worse, it just didn't filter emails at all.

This patch fixes the problem by creating the shm files in /tmp
for DragonFly. With this patch applied, these lines are gone from
the log and emails now correctly contain the X-Spamd-Result header,
AND receiving mails is now much much faster.

For rspamd 1.4.1, we will fix it in dports:

    https://github.com/DragonFlyBSD/DeltaPorts/pull/727

MFH: true

MFH: true

[WebUI] Add graph legend entries for new DSes

Resolves #1300

Issue: #216
Reported by: @fatalbanana

[WebUI] Turn d3pie's stuff into a reusable function,

do not destroy pie on data update