[Proposal] Add support for using a specific sprite for the placement overlay

[Menshin]

Rationale

The current Placement system is handling the placement overlay pretty straightforward : when entering placement mode the global placement overlay entity's sprite is generated from the associated prototype.

Content systems that needs more (construction, pipe layering, etc) can hijack the engine placement system to change its default behavior, but there's no way to change the Sandbox/Mapping native placement behavior.

While this is pretty often enough, situations arise when that limitation becomes problematic : for example, turnstiles can be a pain to place correctly because the default icon/sprite is used (while there are specific sprites showing the turnstill orientation that could be better used in placement mode).

What's proposed here

This PR propose a basic system to allows using a specific sprite on placement mode for a given prototype :

• a new optional placementOverlaySprite field is added to SpriteComponent (could be its own component too), specifying a RSI/State texture.
• if that field is set, the placement system is slightly modified to use this specific texture when building the placement overlay.

Showcase

Placing turnstills on Sandbox mode, using forementioned sprites for placement overlay :

Content.Client_QREX7qnnD5.mp4

Adapting the (content) construction system to use this feature :

Content.Client_GRLe932Iy5.mp4

[Menshin]

@B-Kirill remark applied.

CI weirdly failed on the install dependencies step...

[B-Kirill]

CI weirdly failed on the install dependencies step...

Things happen. Just create an empty commit to restart the tests.

[Menshin]

As requested, moved placementOverlay to its own component.

[Menshin]

Thanks for the feedback and review, the formatting should be ok now.

[Menshin]

Realized there was no reason for the overlay sprite noRotation and scale to be set according to the prototype sprite ones, so decoupled them.

Minus the potential reviews/requests, the PR should be in its final form.

Edit : CI failing for mysterious reasons (integration tests canceled)...