Move from TSLint to ESLint

TSLint is deprecated, we should look into moving to ESLint https://www.npmjs.com/package/tslint

As part of that we should make sure to add the "requires '_'" rule for private members to help with name mangling. https://github.com/dotnet/aspnetcore/pull/30320/commits/7844c64d37b253feb9863cae023be6ec9eff62e4#diff-887211f12c122673d436221142a9cd6cb0c7355385261e595742116180e7754a

"naming-convention": [
            true,
            {"type": "member", "modifiers": "private", "leadingUnderscore": "require"}
          ]

[joaopgrassi]

Hi @BrennanConroy! So, I finally did most of the work. Just an overview:

• Checked all the default rules from TSLint: https://github.com/palantir/tslint/blob/master/src/configs/recommended.ts

• Checked all the default rules from ESLint/TS ESLint: https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/src/configs/recommended.ts https://github.com/eslint/eslint/blob/master/conf/eslint-recommended.js

• Added the ones that were ON by default in TSLint but not in ESLint/TS ESLint.

I believe the only thing missing is adding the rule you mentioned to enfore _ on private fields. I’ll work on it next.

The PR is there in draft, as I believe we’ll have to iterate through it to see I didn’t miss/messed up something. Local build/tests all pass which is a good sign I guess 😅

[BrennanConroy]

Yeah, we’d also like to try and preserve the rules from our tslint config (if they aren’t already on by default)