feature: refactor api parse to g4 (#365)

* feature: refactor api parse to g4

* new g4 parser

* add CHANGE_LOG.MD

* refactor

* fix byte bug

* refactor

* optimized

* optimized

* revert

* update readme.md

* update readme.md

* update readme.md

* update readme.md

* remove no need

* fix java gen

* add upgrade

* resolve confilits

Co-authored-by: anqiansong <anqiansong@xiaoheiban.cn>

tools/goctl/api/parser/g4/test/apis/example.api

@@ -0,0 +1,72 @@
+// syntax: specify the api syntax version,
+// through this version can be a good control
+// api syntax upgrade incompatibility issues
+syntax = "v1"
+
+// Info block is a key-value pair description body,
+// you can add some descriptions of the current api
+// file through this description body, you can add
+// any key-value pair, which does not participate in the api generation
+info(
+    title: sample of api
+    desc: "you can add a newline
+description by quotes"
+    author: songmeizi
+    anyAnotherKey: anyTnotherValue
+)
+
+// The structure in the api evolved from the structure of golang,
+// and it is also reserved to support the structure of golang.
+
+// a golang structure
+type Foo struct{
+    Foo int
+}
+
+// api structure
+type Bar {
+    Bar int
+}
+
+// structure group
+type (
+    FooBar {
+        Foo int
+        Bar bool
+    }
+)
+
+// Like the info block, @server can define any key-value pair.
+// The difference is that @server is a description of the service
+// block or route, which will participate in the api file generation.
+// There are several important keys that need to be understood,
+// which have special meanings. The jwt key is to declare that code
+// generation needs to include jwt authentication logic. The group key
+// is to declare that the files generated by the code need to be grouped
+// according to the value corresponding to the group. The handler key
+// determines the handler in golang. Layer file logic generation
+@server(
+    jwt: Auth
+    group: foo
+    anyAnotherKey: anyTnotherValue
+)
+
+// service block is the description of the api service,
+// including @doc block, @handler and api routing information
+service foo-api {
+    // shortening doc declaration
+    @doc("foo")
+    // shortening handler declaration
+    @handler foo
+    // route
+    get /foo (Foo) returns (Bar)
+
+
+    @doc(
+        summary: foo
+    )
+    @server(
+        handler: bar
+    )
+    post /bar (Foo)
+}