fix: gRPC await promise transpilation, bump ECMAScript target to ES2018

[kon14]

This PR resolves a huge bug around await usage in gRPC handlers being incorrectly transpiled into yield outside generators.

Example (a section of Database module's createView() gRPC handler):

try {
    await this._activeAdapter.createView(
        call.request.schemaName,
        call.request.viewName,
        call.request.joinedSchemas,
        call.request.query,
    );
        callback(null);
    } 

This should in theory transpile into code that only executes the callback after the promise has returned.
Alas we got this:

try {
    yield this._activeAdapter.createView(call.request.schemaName, call.request.viewName, call.request.joinedSchemas, call.request.query);
    callback(null); // @dirty-type-cast
}

Modifying the original TypeScript code so that the callback would execute inside a .then() instead of after an await successfully resulted in this:

try {
    this._activeAdapter.createView(call.request.schemaName, call.request.viewName, call.request.joinedSchemas, call.request.query)
        .then(() => callback(null));
}

But that solution seems like a huge step backwards in terms of readability and would otherwise result in an error-prone codebase.
Thankfully, this bug seems to be resolved in recent ES targets, where await is natively supported.
The actual issue is probably related to TypeScript#6242, although in my tests ES6 wasn't enough.

We could technically bump everything except for the libraries all the way up to es2022 without requiring a Ts or Node container image bump, but I decided to stick with ES2018 across the board for now.

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update
• Refactor
• Build-related changes
• Other (please describe)

Does this PR introduce a breaking change?

• Yes
• No

The PR fulfills these requirements:

• It's submitted to the main branch
• When resolving a specific issue, it's referenced in the PR's description (e.g. fix #xxx, where "xxx" is the issue number)

[ghost]

👇 Click on the image for a new way to code review

Legend