feat(file_system): Add remove(path) and remove_contents(path)

Description

Adds convenience methods for removing a file or directory (taking std::filesystem::path) as well as for removing the contents of a directory (but not the directory iteself)
Updates example to show use of the new methods

Motivation and Context

Current filesystem required you to manually iterate through all the contents of a directory and remove them manually (and you had to properly use unlink or rmdir depending on the type).

This simplifies use by providing some nice convenience functions on std::filesystem::path.

How has this been tested?

Building and running file_system/example on QtPy ESP32s3.

Screenshots (if appropriate, e.g. schematic, board, console logs, lab pictures):

CleanShot 2024-07-01 at 13 57 50

Types of changes

[ ] Bug fix (non-breaking change which fixes an issue)
[x] New feature (non-breaking change which adds functionality)
[ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
[x] Documentation Update
[ ] Hardware (schematic, board, system design) change
[x] Software change

Checklist:

[x] My change requires a change to the documentation.
[x] I have added / updated the documentation related to this change via either README or WIKI

Software

[x] I have added tests to cover my changes.
[ ] I have updated the .github/workflows/build.yml file to add my new test to the automated cloud build github action.
[x] All new and existing tests passed.
[x] My code follows the code style of this project.

esp-cpp / espp

feat(file_system): Add remove(path) and remove_contents(path) #267