Dingpf/upgrade to protobuf

[dingp]

Adding absl as a dependency, also link protobuf and absl::status in the main library.

There was an inexplicit dependency on absl::status used by ers_schema_test, which is not explicitly specified and caused errors like:

 error adding symbols: DSO missing from command line 

The symbol was released to absl::lts_20230125::Status::UnrefNonInlined(unsigned long)

[dingp]

This is to be merged when we switch to the new external software stack (ext-1.1 for SL7, and ext-2.0 for AL9).

In the new external software stack, we have protobuf 3.22.2 and gRPC 1.56.2.

[dingp]

This is replaced by #36 (changed branch name so that it's better suited to be used in other repos).