FEATURE: Pass tags to be flushed to content cache backend

[Sebobo]

What I did

Instead of calling the cache backend for each tag to flush
individually, the list of tags is passed to the backend with
the newly introduced flushByTags method in
neos/flow-development-collection#2718.

This allows each type of backend to optimise the flushing
of all tags, which can lead to huge performance improvements.
Especially when content is published to the live workspace
which leads to large numbers of cache tags that will be flushed.

Also the messages stored with individual content cache tags
take up a lot of unnecessary memory in production
context and not are even used there.

With this change the behaviour can be enabled via
the setting Neos.Neos.fusion.contentCacheDebugMode.

Resolves: #3640

How I did it

The ContentCacheFlusher now calls the flushByTags method introduced in neos/flow-development-collection#2718.

Only in the newly introduced debug mode the old style of flushing by tag individually is used to provide the individual logged feedback why entries were flushed.

How to verify it

Checklist

• Code follows the PSR-2 coding style
• Tests have been created, run and adjusted as needed
• The PR is created against the lowest maintained branch

[mficzel]

Works and makes sense.

One thing that could be added would be to enable the debugMode in development context by default.

The tests can only turn green with neos/flow-development-collection#2718 merged into flow.

[kdambekalns]

What do you think about enabling debug mode in development context by default?

[Sebobo]

I think inspecting the atomic cache debug output is a very specific use case, IMO this should be left disabled until needed.
The output whether entries were flushed at all and how many tags were flushed is still there independent of the new debug flag.
We spend so much time in Development context and there is no need to make it slower than it must be.

[mficzel]

I agree to the argument of @Sebobo that not every flushed tag should be logged even in dev-mode. It can be enabled for debugging caches but other than that i is a risk of covering up important log messages.