Upgrade to PHP 8.4

[spaze]

Follow-up to #159 (Upgrade to PHP 8.3)

• Start testing on PHP 8.4 except Psalm #437
• PHP 8.4 packages oerdnj/deb.sury.org#2176
• Update package nette/di #459 for the lazy: true config option, see blog post
• Upgrade to PHP 8.4 #460
• Stop testing on PHP 8.3 except Psalm #461
• Enable nette/di lazy mode #465
• Test Psalm on PHP 8.4 #439
• Bump PHP requirement to ^8.4 in composer.json #462

[spaze]

The code is running on PHP 8.4 now except Psalm analysis in dev env which still uses 8.3 as Psalm is not compatible with 8.4 yet. #439 and #432 clean that up so I guess I can close this issue as done.