Use new UPF Info configuration

Changes

• Remove custom upf_info configuration
• (Re)-use UpfInfo model from 3GPP TS 29.510 (see oai-cn5g-common-src!24 (merged))
• Fixed validation of UpfInfo

Fixes

• Now we can use the same slicing values and use anchors (see oai-cn5g-fed!142 (merged))
• Closes #6 (closed)

Tests

I ran local tests. @defosseu CI will fail, we need to use the config from oai-cn5g-fed!142 (merged)