App freeze fix, zip changes and assets mapping

[mpsonntag]

This PR introduces the following major and minor changes:

Changes in the DOI registration procedure

• the DOI preparation server now clones the request GIN repository to a directory different from the hosting directory. This directory can be defined via the doienv environmental variables config file. The specific variable name is preparation.
• the zip functionality now actively excludes the .git folder from the zip file. The derepoCloneDir function has been removed from the registration procedure. This leaves the cloned repository intact in the preparation directory on the host machine and can be used for manual registration steps e.g. upload of annexed data to the DOI fork of the repository.
• the Dockerfile also supports the newly introduced preparation folder.

Removing the application freeze on git annex uninit

The removal of the derepoCloneDir resolves the issue of very large datasets freezing the registration process on the git annex uninit step. For details see issue #78. It is still unclear why the application freeze had happened, but tests with repositories that consistently froze the service in multiple test runs now succeed without any issues.

Providing the '/assets' content to a docker host

The DOI registration service and the static DOI hosting service both use the same 'assets'. Until now the assets from /assets had to be manually copied to the DOI hosting service when changes to the assets were made after deploying a new version of the DOI registration service. The PR introduces a docker_startup.sh shell script as a new entrypoint for Docker deployment. This script copies the content of the 'assets' folder to the /doidata volume after the docker container has been started. This ensures, that the host, that is using the /doidata volume to statically provide registered DOI datasets, now automatically has access to the same 'assets' as the DOI registration service. Closes #85.

Minor changes

• the local zip function has been renamed to runzip to avoid any potential name clashes with the standard library package archive/zip.
• the MakeZip function is copied from the 'G-Node/libgin' library, since it is only used by gin-doi and none of the other gin libraries; it is also unlikely that it will be used by another gin library. The code added also includes a basic test.
• updated funding information handling: FunderName and AwardNumber now use ";" as default splitstring and "," as fallback splitstring for backwards compatibility. Closes #84.

[coveralls]

Pull Request Test Coverage Report for Build 614587892

• 48 of 94 (51.06%) changed or added relevant lines in 3 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage increased (+3.6%) to 12.373%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
cmd/gindoid/config.go	0	1	0.0%
cmd/gindoid/dataset.go	36	81	44.44%
<!--	Total:	48	94	51.06%	-->

Files with Coverage Reduction	New Missed Lines	%
cmd/gindoid/dataset.go	1	12.71%
<!--	Total:	1		-->

Totals
Change from base Build 554380259:	3.6%
Covered Lines:	207
Relevant Lines:	1673

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💛 - Coveralls