Attempt to make init-containers a proper shell script

Added auxiliary_SetIndexes.js:

- auxiliary script that includes commands to be run by mongo to set indexes in roslog. It should be possible to call mongo in bash and tell it to load roslog and execute this script on it. Mongo will exit once the script is done.

Changes to init-containers:

- added mechanisms to retrieve own path (useful for a couple of the steps) and a mechanism to retrieve the path to roslog files tf.json and logged-designators.json (which is given as a script parameter or pwd as default if the script parameter is empty). These additions should work as they are; if bash would spot an error in the paths (for example path not found), it would report it. The changes include a few strategic echo commands to allow the user to know what the script assumes the paths to be.

- added a call to an auxiliary *.js script which includes the commands that would previously be run in a mongo shell. This -should- work ... mongo doesn't think it wrong to be called this way, at least. A definitive test that those indices are indeed created was not done yet however.