Use Rainbow directly instead of relying on String refinement.

[jan-bw]

Description

Use the Rainbow gem directly (i.e. Rainbow("text").red) instead of relying on the String monkey patching.

I checked for usage of the following methods:

• background
• bg
• black
• blink
• blue
• bold
• bright
• color
• cross_out
• cyan
• dark
• faint
• fg
• foreground
• green
• hide
• inverse
• italic
• magenta
• red
• reset
• strike
• underline
• white
• yellow

Those are the basic methods defined by the rainbow. I skipped the methods covered by the problematic "method_missing".

Motivation and Context

Fix #130

As raised in the #130, the release 1.4.0 impacted performance of a couple apps. The underlying issue is that the rainbow gem is refining the String class and that the method_missing is overwritten.

The refine seems have some performance issues on some of the ruby releases: https://bugs.ruby-lang.org/issues/18572

This PR is a proposal for mitigating this issue without a need of fixing rainbow gem nor upgrading the ruby version. If the changes here aren't too annoying maybe that could be a way to go? :)

How Has This Been Tested?

I run it against one of the endpoint of the affected application.

average response of 100 requests:

• v1.3.0: 816.07ms
• v1.4.0: 951.84ms
• patch: 816.83ms

I am not sure whether there is a way of testing this in any other way 🤷

[etagwerker]

@jan-bw Looks good, thank you!

[JuanVqz]

@jan-bw we really appreciate your contribution, thanks!