Simplify the version bump process. ### Description

Simplify the version bump process.

- Use substitution hook in docs to update CDN URL.
  - In `dev` or `prerelease` versions, it will point to `dev` url
  - In `stable` versions, it will point it `vX.Y.Z` url
- Introduce a version bump script `tools/bump_version.py`.


~- Use `bump2version` to bump Python versions (continuing from #2460)~
~- Use `npm version` to bump JS versions~
~- Update `run_docker` script to use latest deployed pre-built docker image when `--pre-built` option is specified.~

### Checklists

- [x] Add new / update outdated documentation

from pyodide_test_runner import run_in_pyodide


@run_in_pyodide
def test_bz2(selenium):
    import bz2

    text = "Hello test test test test this is a test test test"
    some_compressed_bytes = bz2.compress(text.encode("utf-8"))
    assert some_compressed_bytes != text.encode("utf-8")
    decompressed_bytes = bz2.decompress(some_compressed_bytes)
    assert decompressed_bytes.decode("utf-8") == text

from pyodide_test_runner import run_in_pyodide


@run_in_pyodide
def test_bz2(selenium):
    import bz2

    text = "Hello test test test test this is a test test test"
    some_compressed_bytes = bz2.compress(text.encode("utf-8"))
    assert some_compressed_bytes != text.encode("utf-8")
    decompressed_bytes = bz2.decompress(some_compressed_bytes)
    assert decompressed_bytes.decode("utf-8") == text
