Add "Matrix Calculations in Brightway" Section

[michaelweinold]

...this might be useful for developers who need access to matrices (eg. hybrid LCA, etc.).

[michaelweinold]

...just saw we already have a "Matrix Construction" section. Taking suggestions of where to move the new content. Same page? Different page? Something like "for developers"..?

[jakobsarthur]

This is great Michael and seems to be complementary to the matrix construction tab already there. Maybe call it "bw matrix convention vs literature" or something along these lines?

[tngTUDOR]

I suggest the following:

• merge both contents (current overview matrices with the one proposed here)
• keep 2 distinct sub-sections:

1. matrix data
2. matrix calculations

Otherwise, we would need to add a different "section" one for "matrix data" and another for "matrix calculations"