WIP: beginning to refactor network analysis docs

[vyudu]

Probably worth discussing more but my thought here is to make Network Analysis its own section of the Catalyst docs, with subsections for the ODE decompositions, structural properties and chemical reaction network theory, and a third section for advanced stuff that links to CatalystNetworkAnalysis.

Added sections for the new API functions in #1134 and building symbolic functions from the ODEs to the ODE docs. Added a section on complex/detailed balance to the CRNT docs.

Need to: add a section on the deficiency one theorem, bring in the CatalystNetworkAnalysis docs, add code examples to the complex/detailed balance section (including stuff about the precision limitations of isdetailedbalanced)