add specific reviewers for individual modules in jwst/

[zacharyburnett]

@tapastro @melanieclarke it might be advantageous to add specific names to .github/CODEOWNERS for specific modules, so that people are automatically tagged for review by default if a module has a PR and no reviewer is set:

jwst/.github/CODEOWNERS

Lines 6 to 11 in 7a69919

	# developers can own some specific paths
	/.github/ @spacetelescope/jwst-pipeline-developers # CI files
	/* @spacetelescope/jwst-pipeline-developers # top level files only
	/changes/** @spacetelescope/jwst-pipeline-developers # changelogs
	/docs/** @spacetelescope/jwst-pipeline-developers # docs
	/jwst/regtest/** @spacetelescope/jwst-pipeline-developers # regtest code

For instance, according to https://github.com/spacetelescope/jwst/wiki/Maintainers#step-and-subpackage-maintainers we could add

/jwst/combine_1d @stscirij @tapastro 

This would replace the page in the Wiki, and I feel it would be easier to keep maintained as it's in the repository itself and someone who was pinged who is no longer the lead can immediately suggest a successor.