feat(config): make it so you can revert override of apps

[StealthyCoder]

This is to add a way to disable the override, inherit from parent concerning apps running on devices.

Relevant fioconfig code

[mike-sul]

Tangential note: we don't need to support pacman.docker_apps not sure we've ever used it.
We deprecated it in v75 in this commit foundriesio/aktualizr-lite@34f8f70

[doanac]

technically it looks good. Lets see what @kprosise says about the wording

[kprosise]

LGTM, the latest changes seem to address feedback provided by other reviewers. Only suggestion has to do with style, but imho the descriptions communicate the usage well, neither too verbose or terse.

[mike-sul]

My 2 cents on the terms we use. IMHO, we should use the term "Compose apps" not "Docker apps" to make it consistent with the user doc.

[vkhoroz]

LGTM

Once Katrina is happy, this can be merged.

[vkhoroz]

An indentation here seems rather weird.
Maybe, @kprosise can help with it?

At the least, these two sentences should be indented at the same level:

# The following explains what happens if you provide a ","
# The following explains what happens if you provide a "-"

The same applies to these three sentences (about indentation):

# Set the Compose apps to none for devices, this will make the device run no apps:
# Set the Compose apps to preset-apps (all apps on most devices):
# Set the device tag to a preset-tag :

Also, as sentences in these paragraphs are user-facing, they deserve a proper punctuation at their ends, like . or : (and proper spacing, like e.g. no space before a colon).

[kprosise]

Provided suggestions based upon feedback from @vkhoroz.

[kprosise]

Suggested change

	# There are two special characters: "," and "-"
	# The following explains what happens if you provide a ","
	# Set the Compose apps to none for devices, this will make the device run no apps:
	# There are two special characters: "," and "-".
	# Providing a "," sets the Compose apps to "none" for devices.
	# This will make the device run no apps:

[kprosise]

Suggested change

	# The following explains what happens if you provide a "-"
	# Set the Compose apps to preset-apps (all apps on most devices):
	# The system will look in the following locations in order to get the complete config:
	# Providing a "-" sets the Compose apps to "preset-apps" (all apps on most devices).
	# The system looks in the following locations to get the complete config:

[kprosise]

Suggested change

	# Set the device tag to a preset-tag :
	# The system will look in the following locations in order to get the complete config:
	# Set the device tag to a "preset-tag",
	# and the system will look in the following locations to get the complete config:

[kprosise]

Suggested change

	# There are two special characters: "," and "-"
	# The following explains what happens if you provide a ","
	# Set the Compose apps to none, meaning it will run no apps:
	# There are two special characters: "," and "-".
	# Providing a "," sets the Compose apps to "none", meaning it will run no apps:

[kprosise]

Suggested change

	# The following explains what happens if you provide a "-"
	# Set the Compose apps to preset-apps (all apps on most devices):
	# The system will look in the following locations in order to get the complete config:
	# Providing a "-" sets the Compose apps to "preset-apps" (all apps on most devices).
	# The system looks in the following locations to get the complete config:

[kprosise]

Suggested change

	# Set the device tag to a preset-tag :
	# The system will look in the following locations in order to get the complete config:
	# Set the device tag to a "preset-tag",
	# and the system will look in the following locations to get the complete config: