[FEATURE] Add uid to SysDomainCache

If you are building an extension, that outputs
data depending on a selected domain, it is easier
to compare the uid of sys_domain records
than the domainName itself.

Resolves: #57297
Releases: 6.3
Change-Id: Ic1efd3efe043f28ef7737f407d9a200b168d9685
Reviewed-on: https://review.typo3.org/28794
Reviewed-by: Markus Schubath
Tested-by: Markus Schubath
Reviewed-by: Krzysztof Adamczyk
Reviewed-by: Andrea Schmuttermair
Reviewed-by: Markus Klein
Tested-by: Markus Klein