pgcli

Hi folks,

I'm Amjith. I created PGCLI <https://www.pgcli.com>, an Opensource client
for Postgres. It is a command line client with GUI features such as
Auto-Completion and Syntax Highlighting.

My goal for participation is gathering consensus to add support in Postgres
to provide support for accessing metadata about a database without
complicated queries.

For example, in order to get a list of tables in a database I have to run a
query like this:

```
SELECT n.nspname schema_name,
c.relname table_name
FROM pg_catalog.pg_class c
LEFT JOIN pg_catalog.pg_namespace n
ON n.oid = c.relnamespace
WHERE c.relkind = ANY(%s)
ORDER BY 1,2;'
```

Columns query is even more complicated.

It'll be nice to have a simple database view that ships by default that we
can query to get his info.

I'm also interested to know how other GUI tool devs get this info from the
database.

Cheers!
Amjith