schema: prepare for fully-functioning CREATE/ALTER/DROP ACLs

In order to make CREATE/ALTER/DROP ACLs available to users other than
admin, make sure utility functions in schema.lua do not require
excess privileges to execute DDL.

Right now many of schema.lua functions work directly with system
spaces to construct a DDL statement or prepare a nice error message
for the user. Siwtch to virtual system views wherever possible.
System views for system spaces are available to role 'public'
and display the same data as system spaces, but filtered through
the user-specific access lense: i.e. they display only rows which
should be visible to the effective user.

Update test results, since now some error messages slightly differ.
Extend test coverage.

In scope of gh-3250 "Make grant/revoke not require accesses to universe"