Use custom exception types

[KennethHoff]

I noticed that in various places (GitHub search) you are throwing the base Exception type, which is not recommended.

Would it be possible to create a custom base Exception like SanityException and whenever you throw, throw an Exception that derives from it?

Here for example, you could throw a SanitySerializationException such that we - as a consumer of this library - can utilize the catch (SanityException ex) or catch (SanitySerializationException ex) syntaxes.

sanity-linq/src/Sanity.Linq/SanityClient.cs

Lines 234 to 237 in 170cd80

	catch (Exception ex)
	{
	throw new Exception($"Failed to deserialize Sanity response: {content}", ex);
	}