fix: dockerignore config (#4578)

1. cago compiler with link system lib, so  ignore cgo generate files
`/usr/bin/ld` is my local Apple's linker

For example:
```
#16 52.59 # github.com/matrixorigin/matrixone/cmd/db-server
#16 52.59 /usr/local/go/pkg/tool/linux_amd64/link: running gcc failed: exit status 1
#16 52.59 /usr/bin/ld: /tmp/go-link-2126209758/000006.o: in function `_cgo_df8c56550131_Cfunc_Decimal128_Add':
#16 52.59 decimal.cgo2.c:(.text+0x71): undefined reference to `Decimal128_Add'
#16 52.59 /usr/bin/ld: /tmp/go-link-2126209758/000006.o: in function `_cgo_df8c56550131_Cfunc_Decimal128_AddDecimal64':
#16 52.59 decimal.cgo2.c:(.text+0xcd): undefined reference to `Decimal128_AddDecimal64'
#16 52.59 /usr/bin/ld: /tmp/go-link-2126209758/000006.o: in function `_cgo_df8c56550131_Cfunc_Decimal128_AddInt64':
```

2. According to #4535, the `system_vars_config.toml` will be the default config and  `make config` do not generate configuration files. So `system_vars_config.toml` should not be ignored. It's re...