Measure usage with `turso db inspect`

[CodingDoug]

This is derived from work that was already started in #273.

Some suggestions to make that output more insightful:

1. Show the total space used - this is the bottom line for billing and likely the first thing the user wants to know.
2. Indicate which items are tables or indexes
3. Sort the list by a. size descending b. name

So it could be something like this (based on what #273 shows):

Total size: xx KB

TYPE   NAME                                  SIZE (KB)
table  users                                 68
index  some_index_1                          8
table  _litestream_seq                       4
table  _litestream_lock                      4
table  libsql_wasm_func_table                4
index  sqlite_autoindex_schema_migrations_1  4
table  sqlite_schema                         4

The contents of sqlite_schema help discern between tables and indexes.

The total size might want to change units if it gets very large.

[glommer]

Other things that I'd like to see:

• this taking into account replicas, right now I don't see anything changing when I create replicas
• no system tables shown, we should just eat the cost of that.

[CodingDoug]

Is the cost of storage the same in each location? If so, there can just be a multiplier for number of instances. If not, this gets a lot more complex and we have to break down the per-location costs to make it clear where costs are going.

[glommer]

storage costs the same in all locations, so for now we can just multiply. In the future we want to choose which tables get replicated to which locations, so not always will the multiplier work.