Refactor out inlined values in builtin materialized views - #39468

…indexes

- Because we don't need to inline VALUES into the DDLs of our builtin materialized views, we can create a new mz_builtin_log_indexes such that both mz_sources and mz_indexes can query it rather than get sent an iterator of the builtin logs.
- We simply extract inline VALUES code into a new builtin view called mz_builtin_logs then reference it in mz_builtin_indexes
- This comes with the nice benefit of not having to dynamically generate each mz_indexes and define the order statically.
- We can also turn make_mz_indexes into a static MZ_INDEXES like the rest of our builtins
- In a later commit, we'll making the same refactor for mz_sources

- In mz_sources, rather than inline the builtin sources and logs as a VALUES list, read them from mz_builtin_sources
- mz_builtin_sources already existed inside "make_builtin_sources", however it was just never used and was dead code. This is why we delete code in make_mz_sources but don't see a positive diff in this commit. However if you were to look inside make_builtin_sources, the same code we deleted exists there.

…tin_log_indexes

- Move `privileges` to `mz_builtin_log_indexes` from `mz_builtin_sources` 
- Instead of embedding the builtin logs to mz_sources, just join on `mz_builtin_log_indexes`

Simply move make_mz_sources to a static mz_sources to remove an unnecessary function call.

Given we're not sharing iterators across these view generators, we can simplify the code further.