Handle deserialisation of standard types

[adamfowleruk]

Please start with a use case description for a USER of this work
[Who] As an app developer
[What] I need to easily deserialise data in to standard types, as I can already serialise them
[Value] In order to minimise the code and performance penalty in my app of using GroundUpDB

Describe the solution you'd like
A function to auto return the correct type as was previously serialised

Describe alternatives you've considered
Doing this yourself as an app programmer reveals prior knowledge of the key value type. Might not always be possible.

Additional context
See the serialising feature for this #18

Will require:-

• Serialising the C++ type in to an equiv GroundUpDB internal type.
• Probably merging HashedValue and EncodedValue (in order to store type info)
• Storing more type info in EncodedValue as a result
• Flattening and restricting the templates currently in use

Will NOT require:-

• Special index or handling type support for Sets, Maps - that is because the above functionality as about converting to and from bytes, NOT specially handling data structures like we do for setKeyValue(Key,Set)