👑 Store system views in the scheme shard

[n00bcracker]

Description

To modify ACL of system views we need to materialize system view paths in the Scheme Shard.
Scheme descriptions of sys views stay virtual (we can add them to Scheme Cache response).
Implementation of sys views is defined by a enum value stored in Scheme Shard (not by path).
Also we don't touch column and OLAP system views.

Milestones

1. Add a new Scheme Shard type for sys views. Support a new type in all components of YDB.
2. Add compatibility to all YDB components to work either with virtual sys views or materialized
3. Create all sys views at Scheme Shard init stage (with feature flag, should be in next major release)

Issues

• Add compatibility to Scheme Cache to work with materialized sys views paths Support system views materialized paths in SchemeCache #17861
• Add a new Scheme Shard path type for sys views Add a new SchemeShard type for system views and appropriate scheme operations #17860
• Support a new Scheme Shard path type in Scheme Cache Support system view path type in SchemeCache #18244
• Fill PathDescription fields in TxProxy for materialized sys views Fill system view path description in TxProxy #18490
• Fill table metadata for materialized sys view path and pass the sys view type to KQP Pass SysView type through KQP and choose the implementation based on it #18700
• Process system view path type in Viewer backend Support system view path type in Viewer #18895
• Process system view path type in GRPC handlers Support system view path type in GRPC handlers #18896
• Create system views during SchemeShard initialization Create materialized system view paths in SchemeShard during SchemeShard init stage #19436
• Make YDB tests robust to SchemeShard initialization Make YDB tests robust to SchemeShard initialization #19986
• Support a new sysview path type in Cli and Cpp sdk Support a new SysView pathtype in cpp SDK and cli #20096

PRs

• Materialized SysView paths #17608
• added a new path type for system views #18038
• Used default value of EnableSystemViews feature flag in SchemeShard ut tests #18140
• added create and drop scheme ops for sysview path type #18089
• Scheme cache sysview path type processing #18223
• Passed and processed sys view type in KQP #18699
• Added support sys view path type to Viewer backend #18898
• Added processing sys view path type in GRPC handlers #19030
• Pass PathId of sys view source object From SchemeShard to KQP ScanActor #19767
• System views creation in SchemeShard under FeatureFlag #19377
• Remove using hardcoded pathId of olap table in tiering test #20090
• Added support sysview pathtype to cli and sdk #20095
• Get SysView available types for each SourceObject type #20076