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- [x] Add new / update outdated documentation

# http://stackoverflow.com/questions/16541618/perform-a-reverse-cumulative-sum-on-a-numpy-array
# pythran export reverse_cumsum(float[])
# setup: import numpy as np ; r = np.random.rand(1000000)
# run: reverse_cumsum(r)
import numpy as np


def reverse_cumsum(x):
    return np.cumsum(x[::-1])[::-1]

# http://stackoverflow.com/questions/16541618/perform-a-reverse-cumulative-sum-on-a-numpy-array
# pythran export reverse_cumsum(float[])
# setup: import numpy as np ; r = np.random.rand(1000000)
# run: reverse_cumsum(r)
import numpy as np


def reverse_cumsum(x):
    return np.cumsum(x[::-1])[::-1]
