Add `requires-python = ">=3.10"` to pyproject.toml (#4131)

Summary:
We only support python 3.10/3.11/3.12 right now, so make that explicit.

The last time I tried to do this, the linter tried to force us to use
new-in-3.10 syntax. I was able to avoid that this time by telling the
`black` formatter to use a larger range of python versions.

Also modify setup.py to be 3.8 and 3.13 compatible so that it can run
and complain about the version mismatch instead of just failing to run.

Then, to save users some time, check the version in
install_requirements.sh before doing any real work.

And `cd` to the script's directory before starting so that users can
invoke it like `/path/to/executorch/install_requirements.sh`.

Pull Request resolved: https://github.com/pytorch/executorch/pull/4131

Test Plan:
Built wheels in CI by adding the `ciflow/binaries/all` label.

Linted all python files:
```
find . -type f -name "*.py" | grep -vE 'third-party|cmake-out|pip-out' > /tmp/f
lintrunner --paths-cmd='cat /tmp/f'
```

Also created a conda environment with python 3.8 and ran
`install_requirements.sh` (without the fail-fast check). It used to
fail on syntax errors, but now it fails because the version can't be
satisfied.

To test the fail-fast logic, ran install_requirements.sh in 3.8 and 3.10
conda environments, and saw that it failed/passed as expected.

To test the failure cases, made some local modifications and saw that it
continued to build the wheel after printing a warning:
- Remove/rename pyproject.toml
- Remove the `requires-python` line from pyproject.toml
- Modify the `requires-python` line to contain an invalid range
- Import a missing module in the `python_is_compatible()` code

To test the new `cd` logic:
```
cd build
../install_requirements.sh  # This worked
```

Reviewed By: mergennachin

Differential Revision: D59291599

Pulled By: dbort

fbshipit-source-id: 5bfc97346180b65ad8719753c4126af025a41ae0