refactor: migrate all functions under function handler 🌱✨

[42atomys]

Description

This pull request represents a significant milestone in our ongoing project to migrate all functionalities from sprig to the new sprout function handler. This transition allows for a phased approach, setting the stage for subsequent enhancements.

Changes

• Refactored all functions to be methods of the FunctionHandler struct.
• Improved test coverage to ensure all functions perform as expected.
• Categorized functions into appropriate groups: misc, urls, semver, maps, slices, regexp, conversion, network, crypto, time, filesystem, encoding, numeric, strings, and random.

Fixes #13 #15 #16 #17 #18 #19 #20 #21 #22 #23 #24 #25 #26

Checklist

• [x] I have read the CONTRIBUTING.md document.
• [x] My code follows the code style of this project. (This pull request define it :trollface:)
• [x] I have added tests to cover my changes.
• [x] All new and existing tests passed.
• [ ] I have updated the documentation accordingly.
• [x] This change requires a change to the documentation on the website.

Additional Information

This pull request consolidates all necessary migration tasks into a single update due to the complexity and interdependencies of the changes involved. This strategic choice accelerates our transition without compromising the integrity of our functionalities.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 99.70480% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 99.7%. Comparing base (15366c6) to head (421df0b).

Files	Patch %	Lines
maps_functions.go	96.0%	2 Missing and 2 partials :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #14 +/- ## ======================================== + Coverage 76.6% 99.7% +23.0% ======================================== Files 16 13 -3 Lines 1511 1398 -113 ======================================== + Hits 1158 1394 +236 + Misses 264 2 -262 + Partials 89 2 -87 ```

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[andig]

What about https://github.com/Masterminds/sprig/pull/62?