Provide repo information

[ilyakaznacheev]

Great tool, but to make it useful for an average user, please add:

• [x] meaningful description of its features
• [x] examples
• [x] screenshots
• [x] installation guides
• [x] optional prepare is to be installed via SAPlink and/or abapGit to automate the installation
• [x] add .abap extension to source files to enable syntax highlighting

[ysichov]

Done