Swap dependency tracking source

[afgane]

Followup to #182 (and issue #186) swapping out use of submodules for dependent roles to using ansible-galaxy command: ansible-galaxy install -r requirements_roles.yml -p roles. Installation docs still need updating plus see how Travis deals with the swap.

[afgane]

@mvdbeek @drosofff It seems the data_managers role just installs a set of data managers tools and it doesn't do anything else. Couldn't we just have the list of data managers be provided as a tools list in the repo and omit that role? With the recent changes to the galaxy-tools role and a shift of ephemeris for the scripts, the role will need to significantly reworked making it a second place to modify the shed_install script (and in the mean time it's failing).

[mvdbeek]

With the recent changes to the galaxy-tools role and a shift of ephemeris for the scripts, the role will need to significantly reworked making it a second place to modify the shed_install script (and in the mean time it's failing).

Absolutely, that needs to happen. Feel free to remove the role, otherwise I can also do that.

[afgane]

This looks ready to go I believe. Let me know if you'd like to see something else updated with this migration.

[drosofff]

👍 Thanks @afgane