Add OnlyIfUnchanged parameter to CreateUpdate & Delete operations

[sarangan12]

Specification for this PR
Currently in the SDK we expose ETagOperationOptions which has AccessCondition. It should be removed. We should not expose it. Instead, we need to introduce a boolean value OnlyIfUnchanged. This value must be used to determine if the etag value should be sent to the server or not.

1. For CreateOrUpdate, this is straight forward: we already take entire models that have an ETag, so you just get that and, if onlyIfUnchanged is true, pass the If-Match header.
2. For Delete, which takes stringName as inputParameter, Unconditionally delete resources.
3. For Delete, which takes the model as inputParameter, Use onlyIfUnchanged similar to CreateOrUpdate.

This is related to issue #8517

@xirzec Please review and approve
@ramya-rao-a FYI

[xirzec]

Approved with a couple minor suggestions