feat: multiple search indexes (#2514)

* refactor: abstract search interface

* wip: ~

* fix cycle import

* objs update hook

* wip: ~

* Delete search/none

* auto update index while cache changed

* db searcher

TODO: bleve init issue

cannot open index, metadata missing

* fix size type

why float64??

* fix typo

* fix nil pointer using

* api adapt ui

* bleve: fix clear & change struct

internal/conf/const.go

@@ -40,13 +40,15 @@ const (
 	PrivacyRegs         = "privacy_regs"
 	OcrApi              = "ocr_api"
 	FilenameCharMapping = "filename_char_mapping"
+	SearchIndex         = "search_index"
 
 	// aria2
 	Aria2Uri    = "aria2_uri"
 	Aria2Secret = "aria2_secret"
 
 	// single
-	Token = "token"
+	Token         = "token"
+	IndexProgress = "index_progress"
 )
 
 const (