refactor(cubesql): Introduce Portal with Empty state

[ovr]

Refactoring: Portal requires Prepared Statement as input, but prepared statement can be empty. Before this PR we used workaround with Option, which is not blocker for implementing pg_catalog.pg_cursors.

[codecov]

Codecov Report

Merging #5317 (03b8f4c) into master (363b42d) will increase coverage by 8.55%.
The diff coverage is 62.22%.

@@            Coverage Diff             @@
##           master    #5317      +/-   ##
==========================================
+ Coverage   75.62%   84.18%   +8.55%     
==========================================
  Files         275      135     -140     
  Lines       33015    21330   -11685     
  Branches     2945        0    -2945     
==========================================
- Hits        24968    17956    -7012     
+ Misses       7539     3374    -4165     
+ Partials      508        0     -508     

Flag	Coverage Δ
cube-backend	?
cubesql	84.18% <62.22%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
rust/cubesql/cubesql/src/sql/postgres/extended.rs	88.97% <54.54%> (-1.19%)	⬇️
rust/cubesql/cubesql/src/sql/postgres/shim.rs	68.81% <64.70%> (+0.50%)	⬆️
...ubejs-schema-compiler/src/adapter/PrestodbQuery.js
...bejs-schema-compiler/src/adapter/SnowflakeQuery.js
...kages/cubejs-api-gateway/src/SubscriptionServer.ts
...-query-orchestrator/src/orchestrator/QueryQueue.js
packages/cubejs-base-driver/src/BaseDriver.ts
...ges/cubejs-schema-compiler/src/extensions/index.ts
...ejs-schema-compiler/src/compiler/CubeDictionary.js
...cubejs-server-core/src/core/OrchestratorStorage.ts
... and 134 more

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