Switchable tokenizer (#776)

* [REFACTORING]Rename whitespace_tokenizer to tag_tokenizer for
registration

Name representing its purpose is preferred.

* Add lindera-tantivy to plume-model's dependencies

* Install lindera-tantivy

* Add SearchTokenizerConfig struct

* Add search tokenizers to config option

* Use CONFIG for tokenizers

* Use enum to hold tokenizer config instead of initializing on config phase

* Use guard instead of duplicate default values

* Use as_deref() instead of guard

* Move SearchTokenizer from plume-models to plume-models::search::tokenizer

* Rename SearchTokenizer to TokenizerKind

* Define SearchTokenierConfig::determine_tokenizer()

* Use determine_tokenizer in SearchTokenizerConfig::init()

* Pass tokenizer config to Searcher methods

* Add LowerCase filter to Lindera tokenizer

* Add test for Lindera tokenizer

* Define SEARCH_LANG env to specify tokenizers set

* Run cargo fmt

* Make Lindera tokenizer optional

* Fix typos

Cargo.toml

@@ -78,6 +78,7 @@ postgres = ["plume-models/postgres", "diesel/postgres"]
 sqlite = ["plume-models/sqlite", "diesel/sqlite"]
 debug-mailer = []
 test = []
+search-lindera = ["plume-models/search-lindera"]
 
 [workspace]
 members = ["plume-api", "plume-cli", "plume-models", "plume-common", "plume-front", "plume-macro"]