Fix: GLA Salvage Crate can no longer be removed by scaffolds

[xezon]

• Merge after Fix: Add CRATE flag to SalvageCrate #1675
• Related to Scrap crates can be removed by placing scaffolds #648

With this change the GLA Salvage Crate can no longer be removed by scaffolds. Crates simply stay intact under the scaffold until they are picked up or time out.

Patched

Rationale

It took until around year 2017 for top players to figure out the obscure exploit of removing visible and invisible Salvage Crate objects by placing Scaffolds over them. In top level matches this is now exploited accordingly. The reason this is accepted by top players is the weakness of China against (scrapped) GLA. A fully scrapped GLA Technical for example can present a major problem in the early stages of a China build.

Since this Project aims to strengthen China and make all faction match-ups more playable, this exploit ideally will no longer be required to achieve fair chances for China vs GLA in the future.

The big advantage is clean game mechanics, and no exploits sold as features to achieve some sort of balancing. The big disadvantage is that this fundamentally changes how top level GLA matches are played, which almost always revolve around Scrap scaffold exploits.

For many Noob, Semi and Pro players this change is inconsequential, because they do not use this obscure exploit to gain the advantage.

This change also makes the mechanics consistent with the inability to delete money crates and any other pickable crate, which was implemented with #443.

[ImTimK]

Rage invented it quite a few years earlier, closer to 2012'ish I think. Anyways, for a long time it wasn't a thing at all.

[MTKing4]

Hallelujah

[Stubbjax]

What does the CRATE flag do here?

[xezon]

Documentation added. Looks good.

[xezon]

iDEarikas

The thing that hurt me the most was the scrap deny removal. Unbelievably awful. Some so called 'bugs' like scrap deny have become a part of the game well enough that removing them is absurd and provocative. 20 years of excessive uses gives them the right to not be called bugs anymore and thus they should stay. Any so called 'bug' that will change the gameplay then better stay. Because it's not a bug anymore if it's the mainstream thing. It's just there, you got to deal with it.