…tic#79360)

Resolves elastic#72151 The _sql endpoint offers a `page_timeout` parameter for
customizing how long scroll contexts should be kept open (if needed) and
a `request_timeout` parameter which the docs describe as "Timeout before
the request fails.". Currently, the value of the `page_timeout`
parameter is used as the `timeout` in subsequent _search requests and
not as the timeout in the `scroll` configuration. For the `scroll`
configuration, SQL uses the `request_timeout` parameter. This PR
addresses the issue by swapping the uses of `page_timeout` and
`request_timeout` in querier. Additionally, the PR removes some unused
artifacts that might have caused some confusion: - The `timeout` and
`keepAlive` fields in `Querier`. Instead, `Querier` directly uses the
according fields in `SqlConfiguration`. - The `SqlConfiguration`
parameter from `ScrollCursor.clear`, it's not used but required an
instance of `SqlConfiguration` with all default values. - One overloaded
constructor of `SqlConfiguration` that was only used for calling
`ScrollCursor.clear` (and some tests) and used default values for an
(arbitrary?) subset of the fields. - The fields related to async
requests in `SqlConfiguration`. I'm a bit unsure about this one but the
fields are never read and it does not seem like an SQL specific concern.
The whole creation of the async tasks is handled in
`TransportSqlQueryAction` and the downstream components do not require
the information.