Remove use of Ska.Shell

[javierggt]

Description

Remove uses of Ska.Shell that can be handled with builtin functions.

Interface impacts

None

Testing

Unit tests

• Linux (on HEAD)

Independent check of unit tests by Jean

• Linux

Functional tests

• Do the following on HEAD:

source /proj/sot/ska3/flight/bin/ska_envs.sh 
cd /proj/sot/ska/jgonzalez/git/mica
git fetch
git co ska-shell
export PYTHONPATH=`pwd`
cd test-pr-269/

and then in python:

from mica.report import report
import getpass
import Ska.DBI
from pathlib import Path

user = getpass.getuser()
cwd = Path().absolute()
db = Ska.DBI.DBI(server='sqlsao', dbi='sybase', user=user, database='axafvv')  # as in test_write_reports
report.REPORT_ROOT = str(cwd)
report.REPORT_SERVER = str(cwd / 'test.db3')

for obsid in [20001, 15175, 54778]:
    report.main(obsid)

and check that all image links are there as expected (dir contents are the same as with the latest release and links are not broken).

Also checked that the bash history does not show the older ln -s ... statements.

[taldcroft]

The changes look good on the surface. @jeanconn - do you have any suggestions for how to test this?

[jeanconn]

Sure. The current report writing test really just confirms the report writing code runs without error... I don't think it would catch if an underlying symlink were broken. To explicitly test that, I'd probably just do what test_write_reports is doing, but stop and inspect the outputs before just removing the reports (which is the cleanup at the end of test_write_reports).

[jeanconn]

Looks great to me with that test report.