Activity Catalog for simplified insertion and standardization of activities

[FaithfulDev]

To make it easier and faster to fill out the form fields, it should be possible to choose activities based on a activity catalog. When typing into the activity field the catalog would be checked for potential matches and show a few of them so that user can use them for auto-completing their inputs.

Whenever a inserted activity is not part of the catalog, the user should be warned about that and given the option to add the activity to the catalog. This way, over time, user can add activities they usually do to it. At the same time corporations can provide employees with standard catalog of activities for them as a guideline.

Use of the catalog should controlled via user setting (see #8). There should also be a section in the settings that allows to edit the user-specific catalog (the ones added to the standard catalog).