docs: Use bazel build for generating external deps rst

[phlax]

Signed-off-by: Ryan Northey ryan@synca.io

Commit Message: docs: Use bazel build for generating external deps rst
Additional Description:
Risk Level:
Testing:
Docs Changes:
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[Optional Runtime guard:]
[Optional Fixes #Issue]
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[mattklein123]

Thanks!

[PiotrSikora]

I beleive this broke precheck dependencies:

Traceback (most recent call last):
  File "/source/tools/dependency/release_dates.py", line 20, in <module>
    import utils
  File "/source/tools/dependency/utils.py", line 5, in <module>
    from tools.dependency.exports import (
ModuleNotFoundError: No module named 'tools'

(from: #16430 -> https://dev.azure.com/cncf/envoy/_build/results?buildId=77650&view=logs&jobId=02101c82-0ad6-591f-f821-6c2adfa0913c&j=02101c82-0ad6-591f-f821-6c2adfa0913c&t=2eacb0d3-1406-5ed1-12df-130fbd8dccf7)

[phlax]

thanks @PiotrSikora ill check now...