Convert Secret type to support file secrets

This commit allows file secrets and string literal secrets.

Tested by installing OF with string secrets, then amending the code to
use a file secret. Both times installed the basic auth secrets with the
correct values

Signed-off-by: Alistair Hey <alistair@heyal.co.uk>

Rename workflows as per k3sup

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Rename a test

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Add test for pack CLI

Added test for pack CLI.
Based on failed test, update the osStr value for darwin.

Signed-off-by: yankeexe <yankee.exe@gmail.com>

Consolidate list of apps and reduce repetition

To add an app previously it was very easy to miss adding it's info to the
info command. This changes the way of adding an app to building a list of
app "objects" and then using this list to get the info message and the
installer command.

Signed-off-by: Alistair Hey <alistair@heyal.co.uk>

Add Azure provisioner for inlets-operator

Enables the Azure provisioner for inlets-operator app.

Signed-off-by: Ze Chen <zechenbit@gmail.com>

Display a download progress bar for arkade get

Signed-off-by: Ramiro Berrelleza <rberrelleza@gmail.com>

Add Gitea as an installable app

Signed-off-by: Matti R <matti@mdranta.net>

Write registry creds to a file

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Add terraform CLI

Fixes: alexellis#200

Tested with unit tests and by downloading terraform to my Mac.

Also adds --version to "arkade get" so you can bring down
terraform 0.12.0 etc.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>