Docs(/techniques/compression): Brotli compression performance

[eugleenyc]

This adds notes on Brotli compression options and provides an example.

Closes issue #2834

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/docs.nestjs.com/blob/master/CONTRIBUTING.md

PR Type

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
• Docs
• Other... Please describe:

What is the current behavior?

Issue Number: #2834

What is the new behavior?

Added documentation regarding Brotli performance.

Does this PR introduce a breaking change?

• Yes
• No

Other information

[Tony133]

I pointed out two small changes, otherwise it seems as good as written. 😉👍

[eugleenyc]

@Tony133 added!