pgAdmin 4 commit: Enhance logging by tracking stdout and stderr of subp

Enhance logging by tracking stdout and stderr of subprocess when log level set to DEBUG.

If the process terminates abnormally then the error is not logged which makes it very
difficult to find the reason for failure.

Fixes #5176

Branch
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master

Details
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https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=019932c32374636c4bf87a6023839a080c14e569
Author: Aditya Toshniwal <aditya.toshniwal@enterprisedb.com>

Modified Files
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docs/en_US/release_notes_4_19.rst       |  1 +
web/pgadmin/misc/bgprocess/processes.py | 29 ++++++++++++++++++++++++-----
2 files changed, 25 insertions(+), 5 deletions(-)