Starts refactoring Xenomorph.dm and other xenocode.

[Birdtalon]

About the pull request

This PR attempts to begin refactoring parts of Xenocode. It's all over the place and I had to start somewhere. Starting to forget what I've done so far and this is getting quite big. So this is mainly to keep track of things as my memory is that of a goldfish 🐟

File Structure:

• Moves /datum/caste_datum and associated code out of xeno_defines.dm into caste_datum.dm (new)
• xeno_defines.dm now lives in ./__DEFINES
• /datum/hive_status now lives in hive_status.dm (new)
• /datum/hive_status_ui moved form hive_status.dm lives in hive_status_ui.dm
• /datum/xeno_mark_define moved to xeno_marks.dm (new)
• Client procs for getting playtime now moved to xeno_client_procs.dm

Code:

• Refactors set_hive_and_update(), moves istype(src) to the subclasses for larva and queen
• Refactors xeno numbering, all xeno hives now number 1-999 independently and pick from a list instead of generating rand every time and iterating over GLOB.all_xenos every time.
• Removes unneeded istype(src) in /mob/living/carbon/xenomorph/larva/update_icons() we already have state_overide here for this reason.
• Refactors larva name generation out of update_icons() and into its own generate_name()
• All xenomorph naming is handled by calling generate_name() Removed handle_name() and moved everything to generate_name()
• Calling generate_name() to change from "Bloody larva" to "mature" is now in ...larva/Life() instead of in update_icons() since update_icons() was called on every Life() tick anyway.
• Refactors /mob/living/carbon/xenomorph/Initialize() removes a few duplicate proc calls, generate_name() called twice, recalculate_actions() called twice etc.
• Adds silly name decorator if a Xeno number is 666
• Replaces single letter vars in hive_status.dm

Explain why it's good for the game

Testing Photographs and Procedure

Screenshots & Videos

Put screenshots and videos here with an empty line between the screenshots and the <details> tags.

Changelog

🆑
code: Starts refactoring, standardising and cleaning Xenomorph.dm and hive_status.
add: Little easter egg for 666 xeno number.
/:cl:

[cm13-github]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[cm13-github]

Conflicts have been resolved. A maintainer will review the pull request shortly.

[Birdtalon]

This is going to be a nightmare to review I should have saved the file structure changes to a different PR but didn't think at the time. Frustration at xeno_defines.dm not being for xeno defines got to me 😢

[Birdtalon]

I am going to split this into atomic PR