Sorting Lists

I added sorting to all list endpoints:

• It is configured using the sort query parameter.
• It only works on properties that have the Sortable attribute, so that we don't leak other data or create weird SQL queries. A list of these properties per entity type is stored in SortableMetadata.
• I also added EntityMetadataProvider, which obtains and caches SortableMetadata.
• LocalizedStrings are sorted by the iv culture by default. This can be changed by adding a dot and a two-letter culture code. For example name.cs will prefer to sort by the Czech variant of the Name property and will only use iv as a fallback.
• All endpoints sort by name.iv by default, except AccountListEndpoint which sorts by emailAddress.

Goodbye lists in randomized order every time we deploy the app. :D