(DOCSP-39566) Removes pages not needed for onprem (#289)

Deletes unneeded files causing orphan warnings. All files were on
exclude list in original mms-docs repo except the manage sharded
collections page, which is for a deprecated feature and was marked
orphan. Redirects will be added to the master branch for these pages in
a separate PR

[DOCSP](https://jira.mongodb.org/browse/DOCSP-39566)

[Staging](https://preview-mongodbsarahsimpers.gatsbyjs.io/ops-manager/DOCSP-39566/)
[Latest
Build](https://workerpool-boxgs.mongodbstitch.com/pages/job.html?collName=queue&jobId=668bea97c7e135d459819903)

Author: sarahsimpers