Add richard to /etc/subuid and /etc/subgid on tb-build-03

Being in the tb-builder group is not enough for doing builds on tb-build-03. In addition, @richard should be added to /etc/subuid and /etc/subgid, to be able to create user namespaces.

I think the content of the subuid and subgid files should be something like that:

tb-builder:1000000:100000
gk:1100000:100000
sysrqb:1200000:100000
acat:1300000:100000
boklm:1400000:100000
richard:1500000:100000

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