[Epic] Advanced Linq Queryable support

[leo-schick]

This is a collection ticket for improvements of the QueryProvider introduced via #20

Queryable Implementation matrix

When it is not implemented, the default behavior applies --> meaning: the query is performed on client side, possibly running heavy API loads against the API.

IQueryable function	Implemented	Unit tests exist
Aggregate	No	No
All	No	No
Any	✔️ #51	✔️ #51
Append	No	No
Average	✔️ ⚠️ but cannot be used, see #26 and #27	No
Cast	No	No
Chunk	No	No
Concat	No	No
Contains	No	No
Count	✔️ ⚠️ but cannot be used, see #26 and #27	No
DefaultIfEmpty	No	No
Distinct	No	No
DistinctBy	No	No
ElementAt	✔️ #42	✔️ #42
ElementAtOrDefault	✔️ #42	✔️ #42
Except	No	No
ExceptBy	No	No
First	✔️ #42	✔️ #42
FirstOrDefault	✔️ #42	✔️ #42
GroupBy	No	No
GroupJoin	No	No
Intersect	No	No
IntersectBy	No	No
Join	No	No
Last	No, require revert sorting	No
LastOrDefault	No, require revert sorting	No
LongCount	✔️ ⚠️ but cannot be used, see #26 and #27	No
Max	✔️ ⚠️ but cannot be used, see #26 and #27	No
MaxBy	No	No
Min	✔️ ⚠️ but cannot be used, see #26 and #27	No
MinBy	No	No
OfType	No	No
Order	No	No
OrderBy	✔️	✔️
OrderByDescending	✔️	✔️
Prepend	No	No
Reverse	No, easily possible	No
Select	✔️	✔️
SelectMany	No	No
SequenceEqual	No	No
SequenceEqual	No	No
Single	✔️ #42	✔️ #42
SingleOrDefault	✔️ #42	✔️ #42
Skip	✔️	✔️ #30
SkipLast	No, require revert sorting	No, require revert sorting
SkipWhile	No	No
Sum	✔️ ⚠️ but cannot be used, see #26 and #27	No
Take	✔️	✔️ #30
TakeLast	No, require revert sorting	No, require revert sorting
TakeWhile	No	No
ThenBy	✔️	✔️
ThenByDescending	✔️	✔️
Union	No	No
UnionBy	No	No
Where	✔️	✔️
Zip	No	No

Other topics

• make async calls possible, e.g. ToListAsync or await foreach(var p in myQuery) Implement Async for QueryProvider #29
• revert sorting required for ...Last linq methods https://github.com/bcc-code/bcc-core-api/issues/367