pingap 0.1.7

A reverse proxy like nginx
# TODO

- [x] support add header for location
- [ ] support x-forwarded-for
- [x] error page
- [x] http peer option
- [x] access log
- [x] support format for env logger(or tokio tracing)
- [ ] better error handler
- [x] config validate
- [x] support add tls
- [ ] log rotate
- [x] stats of server
- [x] start without config
- [x] static serve for admin
- [x] status:499 for client abort
- [x] support get pingap start time
- [ ] custom error for pingora error
- [ ] authentication for admin page
- [x] static file serve
- [ ] set priority for location
- [ ] mock response for upstream
- [ ] add remark for config
- [ ] support multi host for location?