feat: page, hash and rootline caches in Redis again, as on TYPO3 10

Since every page view goes through TYPO3 13, the page cache is on the hot
path; TYPO3 10 kept it in Redis, TYPO3 13 had it in MySQL. Same socket and
options as TYPO3 10, but databases 3-5 instead of 0-2, which may still
hold TYPO3 10 entries in a format TYPO3 13 must not read. DDEV gets the
redis add-on for the same setup locally.

Without a Redis connection the backend logs an alert and misses, so pages
still render (slower); a missing PHP redis extension, however, fails hard.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

.ddev/redis/redis.conf

@@ -0,0 +1,13 @@
+# Redis configuration.
+# #ddev-generated
+# Example configuration files for reference:
+# http://download.redis.io/redis-stable/redis.conf
+# http://download.redis.io/redis-stable/sentinel.conf
+
+maxmemory 2048mb
+maxmemory-policy allkeys-lfu
+
+# to disable Redis persistence, remove ddev-generated from this file,
+# and uncomment the two lines below:
+#appendonly no
+#save ""