[fix] README.md

A lot of minor improvements:

• use of applications instead of postulations
• Capitalized first letter (i.e. Apache, Laravel, Traefik, etc.)
• Capitalized acronyme (i.e. PHP, SSL, SSH, URL, etc.)
• Fixed some code backticks
• s/stagging/staging
• Uniformized colon usage (outside bold and without space before)
• Fixed a list (unfortunately Markdown does not provide lettered list out of the box