Feat: Add DescendGreaterOrEqual for the range [last, pivot], and also DescendRange with option (lt, gte]

[singchia]

Can we have some more range operator options for iterating, like lt gte options in Descend and DescendRange.

In my case, I have a json field "create_time" with decimal value, I want to descend search range like [gte, lt), but it seems cannot be done, example:

db exists:

{"create_time": 10}
{"create_time": 11}
...
{"create_time": 1000001}
{"create_time": 1000002}
...
{"create_time": 2000001}

now I want descend search range [1000001, 2000001) and get last 10 values, I don't want use AscendGreaterOrEqual, because it'll skip too much, but if DescendGreaterOrEqual function exists, it'll be much efficient