separate each installable element into it's own modular file

so that everything needed to install/ test/ uninstall each element (task, taskd, at the moment) is self contained and exists in its own file, with an agreed-upon file name convention and essential ingredients. These files don't have to contain executable code, per-se, but must contain a list of each action needed at each step. This removes the task and taskd specific actions from main.sh (tw-install.sh?) and moves them to `~/.task/install/task.install` and `~/.task/install/taskd.install`. This abstraction becomes the model for any installable element.

Start by reading main.sh or tw-install.sh to understand the current task and taskd installation, testing, and uninstallation actions. Define the file-name convention and required action lists, then confirm that task.install and taskd.install are self-contained and that the task-specific actions have been removed from the main installer.

Written by the indexing model from the issue text.