Make mountpoints in `dev` recipe non-overlapping

[surchs]

https://github.com/neurobagel/recipes/blob/b5cf9d86529c43091e7df0c4810d41f3698a2adc/dev/docker-compose.yml#L29-L32

the way we mount LOCAL_GRAPH_DATA is confusing - although it may not directly break.

if LOCAL_GRAPH_DATA is not in ${PWD} (whole point of having the variable), then when the container starts, /usr/src/data will be created inside the container. But because /usr/src is also a mountpoint, this will then create a data directory in ${PWD} that will look empty from the host.

Instead:

• [x] Make the mountpoint an absolute path in the container, e.g. /data so it no longer overlaps with /usr/src
• [x] Update the shell scripts accordingly so they work correctly

[neurobagel-bot[bot]]

:rocket: Issue was released in v0.0.1 :rocket: