* Update abigen documentation
it looks like `make abigen` has been removed and is included under `make devtools`
* Update native-bindings.md
replace `make` with suggestion
This PR:
- reorganizes all documentation pages so they live in the right category
- removes lots of legacy docs
- contains many improvements to active documentation pages
Geth user documentation is now spread across five major categories:
- Install and Build: installation and compile instructions
- Using Geth: this is for pages about general geth usage.
- For dApp Developers: this is for programming guides and functionality specific
to dapp development. All the dev guides for mobile framework and Go APIs live here.
- JSON-RPC APIs: this has its own section because there is now a sub-page for
every name space. I have also added an overview text that explains how to set
up the API servers.
- For Geth Developers: this is for geth contributors