feat: frontend server (#242)

* feat/frontend-server
 ### Add Frontend Service Protocol Buffers
 - Introduced a new Protocol Buffers file `server.proto` in `proto/greptime/v1/frontend/`.
 - Defined the `Frontend` service with an RPC method `ListProcess`.
 - Added message definitions for `ListProcessRequest`, `ListProcessResponse`, and `ProcessInfo`.
 - Included fields for process ID, catalog, schema, query, start timestamp, and client information in `ProcessInfo`.

Signed-off-by: Lei, HUANG <lhuang@greptime.com>

* feat/frontend-server:
 ### Update `server.proto` in `greptime/v1/frontend`

 - Added a newline at the end of the `ProcessInfo` message definition in `server.proto`.

Signed-off-by: Lei, HUANG <lhuang@greptime.com>

* feat/frontend-server:
 Add new proto file to build script

 - Updated `build.rs` to include `proto/greptime/v1/frontend/server.proto` in the build process.

Signed-off-by: Lei, HUANG <lhuang@greptime.com>

* add frontend mod

Signed-off-by: Lei, HUANG <lhuang@greptime.com>

* feat/frontend-server:
 **Add Frontend Info to ProcessInfo**

 - Updated `server.proto` to include a new field `frontend` in the `ProcessInfo` message, providing additional frontend information for processes.

Signed-off-by: Lei, HUANG <lhuang@greptime.com>

* feat/frontend-server:
 Update `server.proto` to modify data types and field names

 - Changed the data type of `id` from `uint64` to `string` in `ProcessInfo`.
 - Renamed field `schema` to `schemas` in `ProcessInfo`.

Signed-off-by: Lei, HUANG <lhuang@greptime.com>

* -

Signed-off-by: Lei, HUANG <lhuang@greptime.com>

* add catalog to ListProcessRequest

---------

Signed-off-by: Lei, HUANG <lhuang@greptime.com>

build.rs

@@ -67,6 +67,7 @@ fn main() {
                 "proto/greptime/v1/meta/procedure.proto",
                 "proto/greptime/v1/region/server.proto",
                 "proto/greptime/v1/flow/server.proto",
+                "proto/greptime/v1/frontend/server.proto",
                 "proto/greptime/v1/index/bloom_filter.proto",
                 "proto/greptime/v1/index/inverted_index.proto",
                 "proto/prometheus/remote/remote.proto",