Relocate Feature Conformance Functions for Better Code Organization (#1535)

docs/api.md

src-electron/db/query-endpoint-type.js

src-electron/db/query-feature.js

src-electron/importexport/import-json.js

src-electron/rest/user-data.js

src-electron/validation/conformance-checker.js

src-electron/validation/conformance-expression-evaluator.js

src-electron/validation/conformance-xml-parser.js

src-electron/zcl/zcl-loader-silabs.js

test/feature.test.js