Fix GMEX table merging and taxonomy

[mpinsky]

• Fixes the table merging issues for GMEX found by Melissa Karp by adopting the approach from DISMAP here
• Fixes a number of taxonomy issues found by Melissa Karp and colleagues where the same species had been entered under different scientific names (because the accepted name had changed through time). This closes Updated BIOCODE table for Gulf of Mexico #46.
• Updates the DISMAP code to output the FISHGLOB format
• Checks for duplicate entries. None found, so closes Duplicated rows in GMEX_std_clean #56
• Updates the GMEX data through 2024 with a new data download from https://seamapdata.gsmfc.org/

I'm requesting a pull into the dev branch, so that we can trial a new way of handling updates.

When we merge this from dev into main and make a release, it would get a new minor version (e.g., 2.1.0) since it has new years in an existing survey. Exciting!