feature: The executor now controls the public action map - meaning actions work without the API, and pages load faster (and much more!)

[jamesread]

This is a pretty major OliveTin change.

OliveTin actions in the configuration file do not necessarily map 1:1 to actions that can be started. The most notable example of this is entities, which "generate" buttons on the web UI from a single config entry. This means that OliveTin has to generate an ID for each individual button that can be started (as going by action titles with variables in them won't work). OliveTin has previously maintained this map in the grpc API, eg:

• "1234" -> Start {{ container.Name }} | Plex
• "4567" -> Start {{ container.Name }} | Minecraft
• "8910" -> Start {{ container.Name }} | Haproxy

The problem is that this map is only updated / generated on requests to the API, specifically GetDashboardComponents. This created the following subtle problems;

• The action ID for entities is actually using a sha256 of the Action Title and the Entity Prefix, which is fine for a low number of entities, but if we're running a couple of entities, like 8 containers on a RPI, a sha256 hash isn't computationally trivial, causing page loads to take a second or two.
• If an API call is made to start an action by ID, like restart_httpd, and nobody has visited the OliveTin webpage yet, the action won't be found; Running from API throws error that action could not be found #305
• The dashboard buttons might easily fall out of sync with what actions can be used ( Web UI keeping old config.yaml actions although config.yaml file has been updated. #155 ).

This change moves the action map into the Executor, which in itself sounds like an incredibly trivial change, but in practice required a LOT of chunky reachitecting of the way OliveTin does things!