Don't get data from graph object in src/constraints/capacity.jl

[abelsiqueira]

Some notes from discussion with @datejada and @gnawin

• The sets of compact assets accumulated_set_using_compact_method is defined by select assets that have asset.investment_method = 'compact', and either asset_milestone.investable = true or asset_both.decommissionable = true.

Sub issue:

• Move lower limit for non-negative flows indices to variable creation