Consistent page path/id methods

Method	Description	Example	Alternative?
`$page→dirname()`	full directory name with num and uid	`2_project-b`	`$page→dirname()`
`$page→diruri()`	full path with sorting num und uid	`1_projects/2_project-b`	`$page→dirpath()`
`$page→id()`	path with uid	`projects/project-b`	`$page→path(false)`
`$page→uri()`	path with translated slugs	`projekte/projekt-b`	`$page→path($lang)`
`$page→uid()`	slug but always untranslated	`project-b`	`$page→slug(false)`
`$page→slug()`	folder name or translated slug	`projekt-b`	`$page→slug($lang)`
`$page→uuid()`	UUID with schema	`page://12345678-90ab-cdef-1234-567890abcdef`

We should try to pave the path in Kirby 3.8, meaning

all alternative methods should be working as intended in the future
where needed methods (or parameter usage) should be marked as deprecated in the comments/docblocks
go through code base and alter references to be consistent with new naming
docs need to be updated everywhere to only show new methods
real deprecation warnings should only be thrown after docs have been updated for a significant amount of time (6-12 months)
removing deprecated methods should follow one major version after deprecation notice

getkirby / kirby