[Feature] Server pagination implementation (#243)

## Major Changes
- Implement a REST style API app in epapi
- Currently implements a GET method for all entity types in the browse menu (both package level and global)
- Provides paginated results per default with query style filtering for reviewed vs unreviewed.
- Provides new paginated templates with thin wrappers per entity types for easier maintainability
- Implements e2e tests for the API

## Minor changes
- Added more comprehensive gitignore to cover coverage reports and other test/node.js etc. data.
- Add additional CI file for API tests that only gets triggered on API relevant changes.

## ⚠️ Currently only works with session-based authentication. Token based will be added in new PR.

Co-authored-by: Tim Lorsbach <tim@lorsba.ch>
Co-authored-by: jebus <lorsbach@envipath.com>
Reviewed-on: enviPath/enviPy#243
Co-authored-by: Tobias O <tobias.olenyi@envipath.com>
Co-committed-by: Tobias O <tobias.olenyi@envipath.com>

templates/collections/rules_paginated.html

@@ -0,0 +1,33 @@
+{% extends "collections/paginated_base.html" %}
+
+{% block page_title %}Rules{% endblock %}
+
+{% block action_button %}
+  {% if meta.can_edit %}
+    <button
+      type="button"
+      class="btn btn-primary btn-sm"
+      onclick="document.getElementById('new_rule_modal').showModal(); return false;"
+    >
+      New Rule
+    </button>
+  {% endif %}
+{% endblock action_button %}
+
+{% block action_modals %}
+  {% include "modals/collections/new_rule_modal.html" %}
+{% endblock action_modals %}
+
+{% block description %}
+  <p>
+    A rule describes a biotransformation reaction template that is defined as
+    SMIRKS.
+  </p>
+  <a
+    target="_blank"
+    href="https://wiki.envipath.org/index.php/Rules"
+    class="link link-primary"
+  >
+    Learn more &gt;&gt;
+  </a>
+{% endblock description %}