feat(lwc-compiler): Remove old label syntax

[pmdartus]

Changes

Eliminate from the compiler the old (and hacky) way to reference a label from a component

import { Element } from 'engine';		
 		
export default class Test extends Element {
    static labels = ['MyLabel.acceptButton', 'MyLabel.cancelButton']
}

Instead, labels are now imported via using a default import via a @label prefix.

import { Element } from 'engine';
import labelAcceptButton from '@label/MyLabel.acceptButton';
import labelCancelButton from '@label/MyLabel.cancelButton';

export default class Test extends Element {
    labels = {
        accept: labelAcceptButton,
        cancel: labelCancelButton
    }
}

Note: We need to remove the field in Aura before merging.

PR Checklist

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Documentation content changes
• Other... Please describe:

Does this PR introduce a breaking change?

• Yes
• No

[salesforce-best-lwc-internal]

Benchmark comparison

Base commit: 0a8e11f | Target commit: 46b449e

benchmark	base(0a8e11f)	target(46b449e)	trend
append-1k.benchmark:benchmark-table/add/1k	335.93 (± 4.24 ms)	331.44 (± 4.24 ms)	👍
clear-1k.benchmark:benchmark-table/clear/1k	51.34 (± 1.17 ms)	48.37 (± 1.17 ms)	👍
create-1k.benchmark:benchmark-table/create/1k	199.85 (± 1.53 ms)	187.12 (± 1.53 ms)	👍
update-10th-1k.benchmark:benchmark-table/update-10th/1k	182.35 (± 1.94 ms)	181.65 (± 1.94 ms)	👌

[yungcheng]

when this change makes it to Aura (through compiler.js artifact), we would need to update Aura server side POJO to remove the bundleLabels

[salesforce-best-lwc-internal]

Benchmark comparison

Base commit: 6d7ae13 | Target commit: f9005bd

benchmark	base(6d7ae13)	target(f9005bd)	trend