Rename sample logo images

- Attach '_sample' to file names
- Remove `requirements.txt`

.gitignore

@@ -163,3 +163,6 @@ cython_debug/
 inventory_export.csv
 config.py
 .flask_secret_key
+static/images/logo_large.png
+static/images/bel_logo_small.png
+static/images/logo_small.png

requirements.txt

@@ -1,23 +0,0 @@
-# This file is used by pip to install required python packages
-# Usage: pip install -r requirements.txt
-
-# Flask Framework
-click==7.1.2
-Flask==2.0.2
-itsdangerous==2.0.1
-Jinja2==3.0.0
-MarkupSafe==2.0.0rc2
-Werkzeug==2.0.0
-
-# Flask Packages
-Flask-Login==0.4.0
-Flask-Migrate==2.0.2
-Flask-Script==2.0.5
-Flask-SQLAlchemy==2.4.0
-Flask-WTF==0.14.2
-Flask-User==1.0.1.5
-SQLAlchemy==1.3.24
-
-# Automated tests
-pytest==3.0.5
-pytest-cov==2.4.0