Change location of directory check in build_api.sh

This ensures that the log directory is in-place before rake tasks
are run that could generate log entries.
Add cleanup tasks to build_api.sh

Add tasks to clean temporary & cache directories, and clean out
the QA reports queue.  The latter change helps with updates
between revisions that have incompatible reports.
Add comment to build_api.sh
Add script to reinstall vboxadd module

Add script and update README.  The module must be re-installed in
a VirtualBox VM when a package upgrade is done that updates the
Linux kernel.
Merge pull request #12 from dpla/add-vboxadd-script

Add script to reinstall vboxadd module
Change API build to use task for clearing reports

Have build_api.sh use the `contentqa:delete_reports' task instead of
using `rm -rf'.  It's safe to do so now because all branches of the
`platform' app that lacked this task are now merged.
Ensure that `unicorn' is found after frontend provisioning

Issue #7707: https://issues.dp.la/issues/7707

The build_frontend.sh script for the deployment of the frontend
(portal) app needed to have `rbenv rehash' added to ensure that
the `unicorn' executable could be found after the installation of
its gem.
Ensure availability of executables in API build

See https://issues.dp.la/issues/7707

To avoid issues related to #7707 with the API app, add `rbenv rehash'
after the `bundle install' command.
Handle stale pidfiles, API and frontend apps (#7712)

See https://issues.dp.la/issues/7712
Merge pull request #5 from dpla/improve-api-build

Improve api build
Merge pull request #13 from dpla/7712-improve-api-restart

Handle stale pidfiles, API and frontend apps (#7712)
Change location of default for variable

Change frontend_branch_or_tag to be given its default value in
the frontend role's defaults file (defaults/main.yml) instead of
via a default() filter in the deployment task.
Fix database encodings in config files

Align application configuration files with the database encodings
specified in tasks that create the databases.
Add PostgreSQL client package to frontend servers

It aids with troubleshooting to have the psql client.  It won't
be installed otherwise on a server like staging or production where
the database and frontend aren't on the same machine.
Change Omeka database table prefix

This moves it inline with existing installations that have to be
migrated.  I assume that, at this early stage, nobody's relying on
the Omeka site yet in their development VMs. :-)
Fix directory obliteration in Exhibitions deployment

Exclude the correct "files" directory fromt the rsync command that
deploys the Exhibitions app, to keep its contents from being
deleted.  Also be more specific about the directory ownerships and
permissions in the "files" directory.
Add staging files
Add api nodes to postgres db's allowed hosts

This omission became apparent after trying to put the PostgreSQL
database on a server of its own.
Add mail role to common configuration
Add ingestion tasks