Maintenance of OBSTOOLS

Context

Currently, the compilation of the tools OBSTOOLS (src/tools/OBSTOOLS) fails both in branch_5.0 and branch_4.2. The OBSTOOLS source code involves modules from src/OCE/, mostly through symbolic links, but has not been kept up-to-date with recent changes therein.

Proposal

In a first phase, the compilability of OBSTOOLS will be restored. In a second phase, the OBSTOOLS tools should be reviewed, and, if required, updated accordingly.

As part of the second phase, it is proposed to include the compilation of the OBSTOOLS tools, and to limited extent the use of some of these tools (facilitated by minor updates), into the ORCA2_ICE_OBS SETTE testing set-up of branch main.