[Lua, Fishing, Quest] Convert "Under the sea" to IF

[Flibe-XI]

I affirm:

• [x] I understand that if I do not agree to the following points by completing the checkboxes my PR will be ignored.
• [x] I understand I should leave resolving conversations to the LandSandBoat team so that reviewers won't miss what was said.
• [x] I have read and understood the Contributing Guide and the Code of Conduct.
• [x] I have tested my code and the things my code has changed since the last commit in the PR and will test after any later commits.

What does this pull request do?

Compiles all the "Under the Sea" logic in standard format into a single file. Also first in a line of quests that are also in need up converting to single file format. Oswald, Zaldon, and Celestina contain a lot of separate quest logic, which has been cleared to ensure quest files are working properly.

Steps to test these changes

!exec player = GetPlayerByName( !exec player:setFame(4, 49) Talk to Yaya, she has standard text !exec player:setFame(4, 50) Talk to Yaya; starts quest Talk to Oswald Talk to Jimaida Talk to Zaldon Get a fat greedie !additem 4501 Trade it to Zaldon, get key item "etched ring" Talk to oswald, quest complete