feat: Deploy staging site with Kubernetes 🦭

[darcywong00]

@tim-eves - Would you be avaible sometime the week Aug 21-25 to help us deploying the staging branch to api.keyman-staging.com?

Similar to the work you did on keymanapp/help.keyman.com#616, keymanapp/help.keyman.com#641, keymanapp/help.keyman.com#676?

If not available, then maybe we schedule for later in September

[mcdurdin]

Notes here:

• Database needs to be persistent
• Consider strategy for database rebuild -- currently uses a webhook and does a background job rebuild to completely avoid downtime. Hot swaps between schemas in the database. Similar pattern probably needed.
• Consider strategy for deployment of site -- needs to hotswap to avoid downtime (something like 5 requests/second on the keyman sites so even short downtime is pretty impactful)

[darcywong00]

@tim-eves started this at EMDC and will continue working in the background.

We 3 can discuss deployment before A17S24.
He proposed an alternative to the API hook with Fleet.