Randomize angle on random map scripts for more map variation

[elexis]

Random map scripts always use the same angle for rivers seas and other map generation every single time. So it is completely predictable where the enemies are from the first second.

After the code is cleaned up by duplication removal (#4805) and using Vector classes (#4845) that well support arbitrary angles, the rotation of the map generation can be completely randomized.

Thus the player has to explore some territory in order to determine the course of action. The match might be recalled for the unique map generation in the best case.

[elexis]

In 20469:

Unify the other axis of the 8 remaining playerPlacementRiver calls following rP20151, refs #4805.
Use the rotateAround function from rP20468, refs #4845.
Freely randomize the river angle on Corinthian Isthmus following rP20295 and rP20468, refs #4855.

[elexis]

In 20910:

Randomize map orientation on most river maps, Gulf Of Bothnia and Migration to remove hardcoded magic numbers and add more variation for the player.
Refs #4855, #4845.

[elexis]

Only maps that don't randomize yet:

Linear Player Placement:

• Hyrcanian Shores
• Kerala
• River Archipelago
• Unknown

Rectangular maps, hence only 4 different angles possible:

• Corsica
• Latium
• Phoenician Levant

Other:

• Guadalquivir River (weird player angle math)
• Danubius (would need trigger script changes)

[elexis]

In 20933:

Randomize map angle on random maps with linear playerposition pattern, refs #4855, #4845.

[elexis]

In 20934:

Randomize map angle on Guadalquivir River and Latium (refs rP20933), fixes #4855, refs

[elexis]

In 20957:

Randomize the river angle on Danubius, refs #4855.

[elexis]

In 21082:

Implement a ConvexPolygonPlacer that returns all points in the convex hull of some given points.
Implements the Gift-Wrapping algorithm to compute the convex hull.

Replace the latter half of the pathplacer with this new placer, refs #892.
Improves the performance a bit, refs #5011.

Use the new placer on Kerala and Hyrcanian Shores to replace the workaround from rP20933, refs #4855
(the area is not supposed to be parallel to the meandering river).

[elexis]

In 21834:

Fix an OOS on rejoin on Danubius following rP20957, refs #4855, fixes #5198.

Vectors are still deserialized as objects without their prototype functions, so doing math on these obejcts fails upon rejoin, refs #4698.
This patch doesn't add any version incompatibilities and players with the patched version can successfully rejoin unpatched games.

Differential Revision: ​https://code.wildfiregames.com/D1548
Reviewed By: temple