Consolidate MemoryBundle

[jerinphilip]

The following free functions should consolidate into a class that deals with all MemoryBundle troubles. The lifetime of the said class attached with the translation model feels like a sensible thing to do. Anything further inside can use a reference or pointer to the said class.

bergamot-translator/src/translator/byte_array_util.h

Lines 7 to 16 in f6d9233

	AlignedMemory loadFileToMemory(const std::string& path, size_t alignment);
	AlignedMemory getModelMemoryFromConfig(marian::Ptr<marian::Options> options);
	AlignedMemory getQualityEstimatorModel(const marian::Ptr<marian::Options>& options);
	AlignedMemory getQualityEstimatorModel(MemoryBundle& memoryBundle, const marian::Ptr<marian::Options>& options);
	AlignedMemory getShortlistMemoryFromConfig(marian::Ptr<marian::Options> options);
	AlignedMemory getSsplitPrefixFileMemoryFromConfig(marian::Ptr<marian::Options> options);
	void getVocabsMemoryFromConfig(marian::Ptr<marian::Options> options,
	std::vector<std::shared_ptr<AlignedMemory>>& vocabMemories);
	bool validateBinaryModel(const AlignedMemory& model, uint64_t fileSize);
	MemoryBundle getMemoryBundleFromConfig(marian::Ptr<marian::Options> options);

With this consolidation, we may also address

1. A format for model packaging
2. Enforced ssplit file. ssplit file is not a vital requirement at the moment and is currently not provided at the extension.

However, it will be easier to consolidate and take on the packaging and breaking changes in a second iteration.

[XapaJIaMnu]

Can we piggy back this: XapaJIaMnu/translateLocally#89
We should do a "best-effort" load strategy with some warnings if something is missing, rather than falling flat when we can deliver some user experience.