Make RA transport chronoshiftable

[PunkPun]

Supersedes #11869

In vanilla red alert transport wasn't chronoshiftable, so subsequently it wasn't chronoshiftable in openra as well. We don't know why, it might be a hacky westwood solution or transport was just forgotten or both. All other ships / vehicles are chronoshiftable, and Transport is even iron curtainable. So I don't really see why this exception needs to continue existing.

Then if we are to make transport chronoshiftable we need to decide what to do with the cargo. There are 4 options:

1. Leave cargo
2. Leave cargo and apply chrono-return to cargo
3. Kill cargo
4. Kill only infantry (and demo truck) cargo

The first option contradicts red alert lore. APC cargo in vanilla RA is cleared out. However in future games (RA2, RA3), cargo is safe. If we were to pick this option we'd also have to make apc keep cargo. It also poses balance issues as you could effectively chrono 13 * (1 + 5 * (1 + 5)) = 403 instead of 13 units.

For the second option: the sequels had one-way chrono, so they didn't have to deal with chronoing back cargo. We could implement this by adding a teleport-back init to all actors stored inside cargo. In a similar way mcv keeps its chrono effect after transforming into a construction yard. Additional question, what should we do with unchronoshiftable cargo?

The third option is lore-friendly. I haven't found anything in red alert that states that chrono only kills infantry. It just so happens that apc can only store infantry, how vehicle cargo is handled isn't clarified.

The last option is lore-friendly and a combination of the other 3 options. It could be implemented by only keeping chronoable cargo and killing the rest. We'd also have to hierarchically scan for cargo (apc's inside transport need their cargo cleared).

---

For this PR I picked the 3rd solution as its by far the easiest, cleanest and causes the least issues.

[matjaeck]

Kill cargo is AFAICT based on the source files what would have happened if they had not excluded transport vessels and helicopter carriers from the teleport ability in later fixups. I could imagine, that this was a safty measure to prevent players from killing expensive units like tanks and helicopters by trying to chrono a transport or carrier vessel. I wonder how this change improves things, other than making a previously impossible thing a thing no one does once they've tried it (and failed horribly).

[abcdefg30]

Imho 3 makes less sense than 4. Killing all cargo means this can only ever be used as offensive feature by chronoing enemy transports. I think infantry, demo truck (and cargo that is not chronoshiftable) should be killed, with the remaining units getting returned after the chrono runs out, and destroyed if they cannot return into the transport.