Extend remoteapprest to add startupdata option

[robertopreste]

Closes #565

The remoteapprest app start CLI command now accept a --startupdata option to provide a file path that will be loaded at startup.

Note: the URL returned by the remoteapprest app start command cannot be used to open the container yet; there are two issues with it:

• the port referred in the URL is not correct
• the URL contains an extra /api/v1/ that needs to be removed

The correct URL is the one printed in the logs; working on a way to return it through remoteapprest.

[codecov-commenter]

Codecov Report

Merging #566 (d775ddd) into master (9ad2c6f) will increase coverage by 0.04%.
The diff coverage is 100.00%.

❗ Current head d775ddd differs from pull request most recent head 2f7bc26. Consider uploading reports for the commit 2f7bc26 to get more accurate results

@@            Coverage Diff             @@
##           master     #566      +/-   ##
==========================================
+ Coverage   95.16%   95.21%   +0.04%     
==========================================
  Files          92       92              
  Lines        4222     4261      +39     
  Branches      271      273       +2     
==========================================
+ Hits         4018     4057      +39     
  Misses        144      144              
  Partials       60       60              

Impacted Files	Coverage Δ
remoteappmanager/cli/remoteapprest/__main__.py	87.60% <100.00%> (+1.23%)	⬆️
remoteappmanager/cli/tests/test_remoteapprest.py	100.00% <100.00%> (ø)

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[flongford]

Overall looks good, thanks @robertopreste - just a couple of comments

[robertopreste]

@flongford I fixed this, so that now the CLI would first check the allow_startup_data policy, and start the container with the given data only if that policy is True.

[flongford]

LGTM!