Build docs and added tutorial files

docs/source/introduction.md

@@ -4,6 +4,53 @@ The Common Python Library (CPL) is a package for python and a development platfo
 
 This CPL docs help you learn, understand and use the package. From your first application to complex apps for enterprises.
 
+## Feature overview
+
+- Expandle
+- Application base
+  - Standardized application classes
+  - Application object builder
+  - Application extension classes
+  - Startup classes
+  - Startup extension classes
+- Configuration
+  - Configure via object mapped JSON
+  - Console argument handling
+- Console class for in and output
+  - Banner
+  - Spinner
+  - Options (menu)
+  - Table
+  - Write
+  - Write_at
+  - Write_line
+  - Write_line_at
+- Dependency injection
+  - Service lifetimes: singleton, scoped and transient
+- Providing of application environment
+  - Environment (development, staging, testing, production)
+  - Appname
+  - Customer
+  - Hostname
+  - Runtime directory
+  - Working directory
+- Logging
+  - Standardized logger
+  - Log-level (FATAL, ERROR, WARN, INFO, DEBUG & TRACE)
+- Mail handling
+  - Send mails
+- Pipe classes
+  - Convert input
+- Utils
+  - Credential manager
+    - Encryption via BASE64
+  - PIP wrapper class based on subprocess
+    - Run pip commands
+  - String converter to different variants
+    - to_lower_case
+    - to_camel_case
+    - ...
+
 ## Explore
 
 - [Getting started](quickstart)