Prepare extension for x64 build

[Kenzzer]

• Updated AMBuild scripts to depend on alliedmodders's hl2sdk-manifests repository
• Updated the package script to distribute the 64bits extension
• Removed the copy of CDetour and replaced it with the one from sourcemod directly (it supports x86_64 assembly, our copy doesn't)
• Fixed a few remaining instances where PtrToPawnAddress should have been used
• Added --targets x86,x86_64 to the CI script

TO-DO :

• Make a x86_64 assembly variant of the input function, available in IEntityDataMapInputFuncDelegate::Alloc
  • [x] Linux
  • [x] Windows

[Kenzzer]

This PR will also require alliedmodders/hl2sdk-manifests#4 to land before we can actually merge.

[Kenzzer]

Leaving a public note here. The PR is still on our radar however we're waiting on the (hopefully positive) resolution of the sourcepawn's Address type crisis. This currently breaks the extension in major ways, and while we could come up with a fix of our own, we cannot be hasty about it.