Use lazycore utils: Clamp and GetLazyRootDirectory

[gusandrioli]

• PR Description
  This PR updates some functions to start using lazycore's utils. This changes all instances of GetLazygitRootDirectory and one instance of Clamp to avoid conflicts.

• Please check if the PR fulfills these requirements

• Cheatsheets are up-to-date (run go run scripts/cheatsheet/main.go generate)
• Code has been formatted (see here)
• Tests have been added/updated (see here for the integration test guide)
• Text is internationalized (see here)
• Docs (specifically docs/Config.md) have been updated if necessary
• You've read through your own file changes for silly mistakes etc

[gusandrioli]

@jesseduffield Updated and ready for review. This is part of clean up process of moving things to lazycore :).

[jesseduffield]

great work @gusandrioli :)