Explicit table naming in examples to prevent errors from shared tables across examples

[nsipplswezey]

The following examples use/reuse the following table name and schema:

"CREATE TABLE IF NOT EXISTS ks.t (a int, b int, c text, primary key (a, b))",

basic
execution_profile
query_history
schema-agreement
select-paging
speculative-execution
tls

The following examples currently use/reuse the ks.t table, with a different schema:
custom_deserializion uses "CREATE TABLE IF NOT EXISTS ks.t (pk int primary key, v text)"
compare-tokens uses "CREATE TABLE IF NOT EXISTS ks.compare_tokens_example (pk bigint primary key)"

Depending on what order the examples are run/rerun locally, the examples can create inconsistent table schemas for ks.t that cause errors in the examples.

This PR changes the keyspace name in all examples to examples_ks and uses the example file name as the table name for all example tables. This should address any errors caused by tables that are shared between examples.

Fixes: #844

Pre-review checklist

• I have split my patch into logically separate commits.
• All commit messages clearly explain what they change and why.
• I added relevant tests for new features and bug fixes.
• All commits compile, pass static checks and pass test.
• PR description sums up the changes and reasons why they should be introduced.
• I have provided docstrings for the public items that I want to introduce.
• [-] I have adjusted the documentation in ./docs/source/.
• I added appropriate Fixes: annotations to PR description.

[Lorak-mmk]

This is going to be a problem again when someone adds new example with conflicting schema - even running examples in CI is not guaranteed to catch that.
Maybe a better option than changing custom_deserializion and compare-tokens would be to change all examples to use table name corresponding to their name, and change keyspace name to e.g. examples?

[nsipplswezey]

Makes sense to me. Updated PR to match the suggestion.
I used the name examples_ks for key spaces because it seemed clearer to me in the examples. I couldn't find any strong suggestions for naming conventions, so if examples or some other name is better, it can be changed.

All examples except cloud run without error both on my local and in CI on my fork https://github.com/nsipplswezey/scylla-rust-driver/actions/runs/6551696037/job/17793439625.

[Lorak-mmk]

Code changes look fine to me. Please update PR description (because it no longer changes just custom_deserializion and compare-tokens) and put more information in the commit message so that future developers don't need to open PR to see motivation for the change ( https://github.com/scylladb/scylla-rust-driver/blob/main/CONTRIBUTING.md )

[nsipplswezey]

Done!

#847 might block CI checks.

[Lorak-mmk]

Yep, could you rebase on main, as #847 is fixed now?

[Lorak-mmk]

Looks fine to me now, I think we can merge after rebasing on main.

[nsipplswezey]

Done!

[piodul]

I've rebased the pull request - there were conflicts in cql-time-types.rs which I had to resolve. Let's wait for the CI to complete.

LGTM from my side - @Lorak-mmk, please review and merge at your convenience.