Create basic structure to allow automatic deployments

[christianlupus]

This PR should allow deployments to the NC app store using simple pushes to the stable branch.

Closes #233

[codecov]

Codecov Report

Merging #433 (94c029c) into master (7dade4d) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##             master    #433   +/-   ##
========================================
  Coverage      0.95%   0.95%           
  Complexity      401     401           
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  Files            13      13           
  Lines          1262    1262           
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  Hits             12      12           
  Misses         1250    1250           

Flag	Coverage Δ	Complexity Δ
integration	0.00% <ø> (ø)	0.00 <ø> (ø)
unittests	0.95% <ø> (ø)	0.00 <ø> (ø)

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[christianlupus]

@mrzapp I tried to use the REST API of the app store of NC. According to their policy, only maintainers and co-maintainers can upload new releases (in addition to the signature process using openssl). Currently, you are the only maintainer. All other people will get a 403 Forbidden answer upon release upload.
I see 2 options here:

1. You provide a login token to your account of the NC app store as a secret in the repo (it is in your account settings under security)
2. You add another co-maintainer to the app who's token can be used.

I am not able to proceed here any further with the main task but need to know what way we should go.

[mrzapp]

@christianlupus thanks for looking into this.

I was unable to find any way to add other accounts as co-maintainers, but I've provided an API token by the name "APP_STORE_TOKEN" in the repo secrets now

[christianlupus]

As I cannot test the syntax without actually doing the release, I will have to hope for the best and give the PR a try. If it does not work, I will have to fix the issues starting from there.