Administration tool: Build mode offer tool to quickly offer large amount of mobs.

[meow20]

What Does This PR Do

Adds a new build mode mode for admins to select hours required and whether to show their role.

Since its easy to click a mob twice or if a mouse doubleclicks, the PR prevents a mob from being offered while it's prompt to possess it is still visible to dchat.

I've read coding requirements and applied the guidelines there to the best of my ability as far as I can tell.

If I knew this pr will affect this many files and require this much code I wouldn't touch it -.- I have no clue what the changes in traits.dm and trait_helpers.dm do and how much they are needed or if they are up to standard so I hope someone takes a good look at them.

The code at line 172 to 176 is bit of a mess but it would require a genius or refactoring the whole proc to make it look more sane I assume.

"/datum/buildmode_mode/offer/handle_click" is mostly yoinked from all other buildmode modes, I have no physical clue what's happening there and why is taking input of a mob at a mouse click so complicated.

Why It's Good For The Game

Only way to offer mobs (outside pre-made stuff like ERT, deathsquad ETC) is to sluggishly select each one of them in the VV dropdown menu, and you will still be asked about playtime requirement and whether to show role each time.

Testing

I offered a carbon mob and a simple mob with various configurations of the build mode + tested that offering from VV dropdown menu still works as intended.

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Declaration

• I confirm that I either do not require pre-approval for this PR, or I have obtained such approval and have included a screenshot to demonstrate this below.

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