config init now leaves out the test sources unless given --all

A section tagged init:"hidden" isn't written to the file config init
generates; fts_mock and sleeper are. config init --all writes them too.
They still load, and the config commands read and set them as before.

internal/config/conf_sources.go

@@ -13,15 +13,17 @@ const JSCKSources string = "sources"
 
 // JSCSources configures each source of opportunities, one field
 // per source. Each field's cfg tag must match the section's JSCK* constant.
+// The test sources (FTSMock and Sleeper) are tagged init:"hidden", so
+// `config init` only writes them with --all.
 // SkipRulesFile is the JSON file of rules that mark new opportunities
 // Skipped (see internal/skiprules), read again when it changes; empty means
 // none.
 type JSCSources struct {
 	SkipRulesFile string               `cfg:"skip_rules_file"`
 	FindATender   JSCSourceFindATender `cfg:"find_a_tender"`
-	FTSMock       JSCSourceFTSMock     `cfg:"fts_mock"`
+	FTSMock       JSCSourceFTSMock     `cfg:"fts_mock"        init:"hidden"`
 	EUSupply      JSCSourceEUSupply    `cfg:"eu_supply"`
-	Sleeper       JSCSourceSleeper     `cfg:"sleeper"`
+	Sleeper       JSCSourceSleeper     `cfg:"sleeper"         init:"hidden"`
 }
 
 // ---------- Section methods (see Section) ----------