Add `pager` option to `~/.myclirc`

[BuonOmo]

Description

Allow user to set a specific pager without the need of a PAGER env variable. Fixes https://github.com/dbcli/mycli/issues/881

Checklist

• [x] I've added this contribution to the changelog.md.
• [x] I've added my name to the AUTHORS file (or it's already there).

[amjith]

Thank you!

:cheese: