Investigate `nix` usage for `forc index`

[ra0x3]

• More details to come
• @Br1ght0ne, when discussing with this with @Voxelot your name was brought up as a potential nix expert to consult with
• We essentially have an issue where all of the issues that users experience when getting started with the indexer are related to our forc index plugin
  • This plugin does things like compile indexers to a wasm32 target - which can work or not work depending on what type of environment the users have on their machine
  • Users rarely have issues with the fuel-indexer service because we've dockerized it (preventing those ☝🏼 types of issues)
• We'd effectively like to "dockerize" (in a manner of speaking) our forc index plugin in a way that is super easy for users to understand/pickup
• Any thoughts here? Happy to chat on a call or some such

cc @digorithm

[gww-fuel]

maybe helpful:

• += Dockerfile and updated README.md fuel.nix#115