improved semantics for kibana_context function

[ppisljar]

kibana_context function semantics needs improvements. it should not accept any json blob parameters. Instead we should rather create utility functions.

• update query arg to take query expression functions (blocked by [data.query.query] Create expression functions for KQL/Lucene & add toAst method #67895)
• update filters arg to take esFilter expression function (blocked by [data.query.filters] Create expression function for filters & add toAst method #67896)
• update timeRange arg to take timeRange expression function (blocked by [data.query.timefilter] Create expression function for timerange & add toAst method #67897)
• update savedSearchId arg to take savedSearch expression function (blocked by [discover] Create expression function for savedSearch #67901)
• remove usage of getSavedObject execution context (handler) and replace with getSavedObject function as an argument (blocked by [expressions] Create expression function to getSavedObjects #68328)

[elasticmachine]

Pinging @elastic/kibana-app-arch (Team:AppArch)

[ppisljar]

closing this as the majority of work was finished and we have issues open for the remaining items