Reduce the number of requests

[beslst]

At the moment, for every package we do

• resolve package
• get package version
• get latest package version
• do the same for every dependency

what it should be like

• resolve package
• get package version > skip if resolved package is the one we need, resolve has to return the same info as package version though
• get latest package version > do not do this, instead add latest package version to output of resolve package
• do the same for every dependency

so the happy path is 1 request per package, instead of always 3.

[beslst]

Adapted backend to provide the required functionality