Investigate usage of Typescript in indexers

[ra0x3]

• As of today indexers are written in Rust
• Rust is cool & powerful but presents a high(er) barrier to entry for smart contract engineers
  • Smart contract engineers are the target audience here
• We should set aside some dedicated time to determining whether or not we can let users write indexers in Typescript
• This issue's completion is based on either a:
  • Yes it could be feasible to write indexers in Typescript with relatively minimal changes to the project
  • No, it is not feasible to write indexers in Typescript with relatively minimal changes to the project
• We should also update this issue with an explanation on whichever conclusion is reached ☝🏼

Additional notes

• Current indexers compile to a wasm32 target
• Via Fuel's typescript library we can generate JSON ABI the same as we do for rust projects
• The main difference is that we'd need to us something in Typescript to replace our GraphQL schema codegen
• There is also discussion to write indexers in Sway -- which is where the "with relatively minimal changes to the project" in the above outcomes ☝🏼 come from