Inherit APP6 Symbol Set from parent organization

[gjvoosten]

In addition to the Context and Standard Identity, also inherit the Symbol Set from the parent organization.

Closes AB#1184

User changes

• When not explicitly set for an organization, the APP6 Symbol Set is inherited from the parent organization.

Superuser changes

• Superusers can leave the APP6 Symbol Set for an organization empty, in which case it will be inherited from the parent organization.

Admin changes

• None.

System admin changes

• anet.yml or anet-dictionary.yml needs change
• db needs migration
• documentation has changed
• graphql schema has changed

Checklist

• Described the user behavior in PR body
• Referenced/updated all related issues
• commits follow a repo#issue: Title title format and these 7 rules
• commits have a clean history, otherwise PR may be squash-merged
• Added and/or updated unit tests
• Added and/or updated e2e tests
• Added and/or updated data migrations
• Updated documentation
• Resolved all build errors and warnings
• Opened debt issues for anything not resolved here

[midmarch]

Working nice, in this test I defined NATO as being an APP6 ground unit, and the NATO Agencies an APP6 civilian organization.

But I had to reset all (maybe most) existing organizarions, the app6symbolSet column.

[gjvoosten]

But I had to reset all (maybe most) existing organizarions, the app6symbolSet column.

Updated the migration.

[midmarch]

Please merge this PR