Add function and script that return IDs of open positions

[illia-malachyn]

Adding a script to get the IDs of open positions. FCM observer needs this information to query the position health factors.

Update: backported to main #296

[illia-malachyn]

I've just understood that it might be better to write a script that fetches a number of positions with an offset. Sth like:

access(all) fun main(startIndex: UInt64, count: UInt64): [FlowALPv0.PositionDetails];

This is doable and it's a faster way to retrieve positions. I'll update PR with a new script

[illia-malachyn]

I think with such a script it will be easier to manage positions #294

[nialexsan]

@illia-malachyn can you also create a similar PR to the main branch and link it here to keep track of backported features

[jordanschalm]

I prefer this solution over #294. I feel like dealing with both position ID and index is a bit confusing.

If we pair this with a script to batch-retrieve position details by list of position IDs (to avoid needing one script call per position), I think we'll have what we need.

[UlyanaAndrukhiv]

I like the current approach, think it is better cause returns all position ids in a single call.

[illia-malachyn]

If we pair this with a script to batch-retrieve position details by list of position IDs (to avoid needing one script call per position), I think we'll have what we need.

Exactly! That is what I was thinking of as the 3rd approach. I'll add such a script to this PR