add linter to ensure we always await async function calls/promises

[holic]

More often than not, we want to await and not doing so leads to scary bugs. For cases where we explicitly don't want to await, we can add a lint ignore line comment.

https://github.com/typescript-eslint/typescript-eslint/blob/main/packages/eslint-plugin/docs/rules/no-floating-promises.md

[holic]

tried to enable this but ran into some issues

new .eslintrc

{
  "root": true,
  "parser": "@typescript-eslint/parser",
  "plugins": ["@typescript-eslint"],
  "extends": ["eslint:recommended"],
  "rules": {
    "max-len": ["error", { "code": 180, "comments": 180 }],
  },
  "overrides": [
    {
      "files": ["*.ts", "*.tsx"],
      "extends": ["plugin:@typescript-eslint/eslint-recommended", "plugin:@typescript-eslint/recommended"],
      "parserOptions": {
        "project": ["./tsconfig.json"],
      },
      "rules": {
        "@typescript-eslint/ban-types": [
          "error",
          {
            "extendDefaults": true,
            "types": {
              // don't throw an error for the empty object type ({})
              "{}": false,
            },
          },
        ],
        "@typescript-eslint/no-floating-promises": "error",
      },
    },
  ],
}

running pnpm lint in CLI shows this (and does catch some await errors)

/Users/kevin/Projects/latticexyz/mud/packages/cli/dist/index.d.ts
  0:0  error  Parsing error: ESLint was configured to run on `<tsconfigRootDir>/dist/index.d.ts` using `parserOptions.project`: /users/kevin/projects/latticexyz/mud/tsconfig.json
However, that TSConfig does not include this file. Either:
- Change ESLint's list of included files to not include this file
- Change that TSConfig to include this file
- Create a new TSConfig that includes this file and include it in your parserOptions.project
See the typescript-eslint docs for more info: https://typescript-eslint.io/linting/troubleshooting#i-get-errors-telling-me-eslint-was-configured-to-run--however-that-tsconfig-does-not--none-of-those-tsconfigs-include-this-file

but it doesn't seem to be catching the issue in #3119