Trim source-profile link for usnistgov#116.

As discussed in the branch under review in usnistgov#204, we now have absolute
paths in the resolved catalogs based on the full paths to the profile,
which is less than idea for published catalogs.

Comment with explanation:
usnistgov#204 (comment)

Example:
https://github.com/aj-stein-nist/oscal-content/blob/dc5500ed9371b485fc21cb095d2fb9db6e2a1fd3/nist.gov/SP800-53/rev5/xml/NIST_SP-800-53_rev5_LOW-baseline-resolved-profile_catalog.xml#L11

To work around this for the time being, we are using sed in the Makefile
to clean up once profile resolution is done and before the XML source is
converted to the target JSON and YAML.

build/Makefile

@@ -88,7 +88,8 @@ resolve-xml-profiles: $(GEN_XML_RESOLVED_CATALOGS) ## Resolve OSCAL XML profiles
 
 $(GEN_CONTENT_DIR)/%-resolved-profile_catalog.xml: $(SRC_DIR)/%_profile.xml
 	mkdir -p $(@D)
-	$(PROFILE_RESOLVER_RUNNER) $(SRC_DIR)/$*_profile.xml $(GEN_CONTENT_DIR)/$*-resolved-profile_catalog.xml $(PROFILE_RESOLVER_ARGS)
+	$(PROFILE_RESOLVER_RUNNER) $(GEN_CONTENT_DIR)/$*_profile.xml $(GEN_CONTENT_DIR)/$*-resolved-profile_catalog.xml $(PROFILE_RESOLVER_ARGS)
+	@sed -i'' -e "s|file:$(shell realpath $(GEN_CONTENT_DIR)/$*_profile.xml)|$(shell basename $*_profile.xml)|g" $(GEN_CONTENT_DIR)/$*-resolved-profile_catalog.xml	
 
 .PHONY: validate-xml-content
 validate-xml-content: $(GEN_XML_FILES) ## Validate XML files