quiesce-plan-cache (#521)

Summary:

- Current implementation of plan cache provdes zero benefit.
- Logic needs rework.
- This change quiesces the plan cache until such time as the requisite work is prioritised.

test-contains-both-streams (#516)

Summary:

- Added new robot testing keyword `Should Stackql Exec Inline Contain Both Streams`.
- Updated selected positive and negative scenarios to use new keyword.
- Robot test `Registry Pull Google Provider Implicit Latest Version` uses new keyword for positive scenario.
- Robot test `Select Star of EC2 Instances Returns Expected Result` uses new keyword for positive scenario.
- Robot test `Faulty Auth Azure Authenticated VM Sizes` uses new keyword for negative scenario.

sqlite-mathematics-returns (#511)

Summary:

- Improved CICD doco.
- Migrated duplicate functionality to `any-sdk`.
- Restore `sqlite3` mathematical functions.
- Added robot test `Google Buckets List With Date Logic Exemplifies Use of SQLite Math Functions`.

busted-gha-ubuntu-docker (#510)

Summary:

- Short term fix to avoid defective github action runner.
- Non standard runnner version pin.

readwrite-walkthrough

Summary:

- Webserver VM create walkthrough.

scenario-testing-evolution (#502)

Summary:

- Supporting different testing patterns:
    - `readonly`; read ops only.
    - `readwrite`; read and mutate with `stackql`.
    - `deploy`; lifecycle management with `stackql-deploy`.
- CI improvments to elide needless builds.

scenario-testing-evolution

Summary:

- Supporting different testing patterns:
    - `readonly`; read ops only.
    - `readwrite`; read and mutate with `stackql`.
    - `deploy`; lifecycle management with `stackql-deploy`.
- CI improvments to elide needless builds.

- Added verbosity for eyeballing.

improvement-of-scenarios

Summary:

- Change to walkthrough user input delimiters.
- Added `aws` walkthrough.
- Tabulation of results.
- Return code nonzero if **any** test fails.

demo-md-walkthrough-testing

Summary:

- Support for simple testing of walkthroughs written in markdown, with annotations.
- Whole table match scenario.
- Nonempty table match scenario.
- Skip testing on files named `README.md`.
- Runnable from CI, with tag of form: `scenario-<stackql_build_run_number>-<anything>`.