cogs add: failure mode

[matentzn]

Non urgent, but it would be good if cogs add would not fail hard if a fail has been added previously (or is unchanged).

Like git add.

Related to https://github.com/ontodev/cogs/issues/53

[matentzn]

Workaround in the meantime:

1. check whether file is in .cogs directory
2. check (grep) cogs ls
3. Use pipeline ||

cogs:
	$(foreach csv, $(ALL_AXIOM_ANALYSIS_TABLES), cogs add $(csv) || echo "Already added!";)
	cogs push