[IDEA]: Add foundation when creating a seed or migration and remove raw imports#138

### The Idea I think it would be nice to add some more foundation into these files when they are created, just to save the developer a bit more time, eg creating a migration would result in ```ts // Assume i ran `nessie make:migration create_users_table` import { AbstractSeed, Info, ClientPostgreSQL } from "https://deno.land/x/[email protected]/mod.ts"; export default class extends AbstractSeed<ClientPostgreSQL> { /** Runs on seed */ async run(info: Info): Promise<void> { this.client.queryArray(`<type> TABLE <table> ( ... // place your code here )`) } } ``` Also it'd be nice for the imports to use a local deps.ts, *most* people use a `deps.ts` at root level so i think it'll be safe to do `import { ... } from "../../deps.ts"`, this does shave off some time for the user and makes it's that bit more faster to create a migration or seed