add lower bound for feel_steel_secondary that is markedly higher than sm_eps to improve CONOPT convergence

[0UmfHxcvx5J7JoaOhFSs5mncnisTJJ6q]

close https://github.com/remindmodel/development_issues/issues/206

• Bug fix

Checklist:

• My code follows the coding etiquette
• I performed a self-review of my own code
• I explained my changes within the PR, particularly in hard-to-understand areas
• I checked that the in-code documentation is up-to-date
• I adjusted the reporting in remind2 where it was needed
• I adjusted forbiddenColumnNames in readCheckScenarioConfig.R in case the PR leads to deprecated switches
• All automated model tests pass (FAIL 0 in the output of make test)
• The changelog CHANGELOG.md has been updated correctly