Migrating old code that doesn't use the package

Migrating old code that doesn't use the Ocean4DVarNet package is not a major problem.

Version 1.0.x of the package is the code that was available in the starter repository.

All you need to do is :

Install the package in the 1.0.x version :
```
pip install "ocean4dvarnet<=1.1"
```
Delete (or rename for backup) the src directory
```
mv src src.backup
```
Then replace in the code the function/class calls "src/xxx" with "oceandvarnet/xxx". For example, src.models.Lit4dVarNet becomes oceandvarnet.models.Lit4dVarNet.

After validation, you can delete the src directory

rm src