Support single file upload/overwrite in configSet API

After SOLR-10391 was implemented, users are now able to overwrite existing configSets using the configSet API. However the files uploaded are still required to be zipped and indexed from the base configSet path in ZK. Users might want to just update a single file, such as a synonyms list, and not have to tar it up first.

The proposed solution is to add parameters to the UPLOAD configSet action, to allow this single-file use case. This would utilize the protections already provided by the API, such as maintaining the trustiness of configSets being modified.

This feature is part of the solution to replace managed resources, which is planned to be deprecated and removed by 9.0 (SOLR-14766).

The following APIs are being proposed:

V1:

Adding to the configSet upload one urlParam, filePath:

 "http://localhost:8983/solr/admin/configs?action=UPLOAD&name=myConfigSet&filePath=solrconfig.xml&overwrite=true"

V2:

• Uploading a configSet:

   PUT - /api/cluster/configs/{name}

• Uploading a file in a configSet:

   PUT - /api/cluster/configs/{name}/{filename}