🦹‍♂️ Add missing functions to set minimum OS and GPU targets on IRCompiler

[MarijnS95]

By setting the minimum targets that emitted Metal shaders should support, we may not only be opting out of potential optimizations that are only supported on newer OS versions or GPUs (i.e. per the feature tables at) https://developer.apple.com/metal/Metal-Feature-Set-Tables.pdf) but also receive adequate errors when features used in shaders are not supported by the given minimum target, such as:

IRError { code: UnsupportedInstruction, payload: "IR contains unsupported instruction: \"dx.op.atomicBinOp.i32\". Target minimum OS build version does not support texture atomics" }

(This happens when setting the deployment target to MacOS 13, as texture atomics are only supported on MacOS 14 onwards)

Unfortunately the compiler also throws a related error on one of our shaders regardless of the deployment target we set, as if there's a (broken) requirement to not set minimumDeploymentTarget higher than the machine that metal_irconverter is running on?

IRError { code: UnableToLinkModule, payload: "Error linking metallib. Please verify that the minimumDeploymentTarget is equal or lower than your operating system version." }