Multiple enhancements and bugfixes

!Breaking change! - The updated version will not be able to read your old database file

Major improvements:
- Added editable pastas
- Added private pastas
- Added line numbers
- Added support for wide mode (1080p instead of 720p)
- Added syntax highlighting support
- Added read-only mode
- Added built-in help page
- Added option to remove logo, change title and footer text

Minor improvements:
- Improved looks in pure html mode
- Removed link to GitHub repo from navbar
- Broke up 7km long main.rs file into smaller modules
- Moved water.css into a template instead of serving it as an external resource
- Made Save button a bit bigger
- Updated README.MD

Bugfixes:
- Fixed a bug where an incorrect animal ID in a request would cause a crash
- Fixed a bug where an empty or corrupt JSON database would cause a crash

templates/footer.html

@@ -3,8 +3,12 @@
 
 <hr>
 <p style="font-size: smaller">
-    MicroBin by Daniel Szabo. Fork me on <a href="https://github.com/szabodanika/microbin">GitHub</a>!
-    Let's keep the Web <b>compact</b>, <b>accessible</b> and <b>humane</b>!
+    {% if args.footer_text.as_ref().is_none() %}
+        MicroBin by Dániel Szabó. Fork me on <a href="https://github.com/szabodanika/microbin">GitHub</a>!
+        Let's keep the Web <b>compact</b>, <b>accessible</b> and <b>humane</b>!
+    {%- else %}
+        {{ args.footer_text.as_ref().unwrap() }}
+    {%- endif %}
 </p>
 
 {%- endif %}