Make GID its own type to prevent defaulting to 0

[jdolitsky]

A follow up to #1407 which had the unintended side effect of missing gid value defaulting to 0

[pnasrat]

@jdolitsky note the logging out of gid broke with this as the format string is now of a pointer not of the uint32

2025/01/02 16:38:15 INFO   accounts:
2025/01/02 16:38:15 INFO     runas:  
2025/01/02 16:38:15 INFO     users:
2025/01/02 16:38:15 INFO       - uid=1000(build) gid=824636385816
2025/01/02 16:38:15 INFO     groups:
2025/01/02 16:38:15 INFO       - gid=1000(build) members=[build]
2025/01/02 16:38:15 INFO auth configured for: [apk.cgr.dev]

apko/pkg/build/types/image_configuration.go

Line 261 in b8aa761

log.Infof(" - uid=%d(%s) gid=%d", u.UID, u.UserName, u.GID)