update readme documents, mend some broken links and add sig-content repo into infrastructure sig

Signed-off-by: Nminglonghuang <roberthuang1010@163.com>

sig/README-EN.MD

@@ -41,9 +41,9 @@ SIG data is stored in the **sig** directory of the **OpenHamony/community** repo
 ```
 "sigs-List":[
       {
-         "sig-name":"sig-docs",
-         "projects":"https://gitee.com/openharmony-sig/docs",
-         "project-path":"docs/"
+         "sig-name":"sig-python",
+         "projects":"https://gitee.com/openharmony-sig/python",
+         "project-path":"python/"
       },
       {
          "sig-name ":"sig-updates",

sig/README.md

@@ -70,9 +70,9 @@ SIG信息记录统一归档在OpenHamony/community仓库的sig目录内：
 ```
 "sigs-List":[
       {
-         "sig-name":"sig-docs",
-         "projects":"https://gitee.com/openharmony-sig/docs",
-         "project-path":"docs/"
+         "sig-name":"sig-python",
+         "projects":"https://gitee.com/openharmony-sig/python",
+         "project-path":"python/"
       },
       {
          "sig-name ":"sig-updates",

sig/sigs.json

@@ -339,6 +339,7 @@
          "projects":"https://gitee.com/openharmony/website",
          "projects":"https://gitee.com/openharmony-sig/cicd",
          "projects":"https://gitee.com/openharmony-sig/archive",
+         "projects":"https://gitee.com/openharmony-sig/sig-content",
          "project-path":"NONE"
       },
       {