feat: refactor string package remove-first

[steff456]

Part of #1062

Description

What is the purpose of this pull request?

This pull request:

• Refactors the string package @stdlib/string/remove-first
• Adds @stdlib/string/base/remove-first
• Adds @stdlib/string/base/remove-first-code-point
• Adds @stdlib/string/base/remove-first-grapheme-cluster

Related Issues

Does this pull request have any related issues?

This pull request:

• Is part of Tracking issue: refactor string packages handling grapheme clusters in terms of "base" packages #1062

Questions

Any questions for reviewers of this pull request?

• The linter doesn't like the identifier name removeFirstGraphemeCluster because it exceeds 25 characters, should we supress this rule, or there's a shorter name we want to adopt for that package?

Other

Any other information relevant to this pull request? This may include screenshots, references, and/or implementation notes.

No.

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the contributing guidelines.

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@stdlib-js/reviewers

[kgryte]

@steff456 for removeFirstGraphemeCluster, just disable the line rule on a per line basis where the variable is first declared. E.g.,

var removeFirstGraphemeCluster = require( '<pkg>' ); // eslint-disable-line id-length

In Markdown, you'll need to add the following before each JavaScript block.

<!-- eslint-disable id-length -->

[kgryte]

LGTM. Thanks, @steff456!