Restructure and complement of NetHSM documentation

[mmerklinger]

• Add sphinx-tabs dependency to provide examples with tabs.

• Edit chapter "Index"

  • Add prior unused getting started to index and add more information.

• Edit chapter "Getting Started"

  • Add hardware installation chapter to getting started chapter.
  • Seal verification chapter was integrated in getting started chapter.
  • Add improved seal position images.
  • Unify image naming and add smaller images with lower resolution.

• Add chapter "Administration"

  • Integrate new API documentation links.
  • Add topics "State", "Boot Mode", "Unlock Passphrase", "HTTPS API Certificate", "Network", "Time", "Metrics", "Logging", "Factory Defaults", "User Roles", "User Delete", "User Passphrase", "Tags for Users".

• Add chapter "Operation"

  • Integrate new API documentation links.
  • Add topics "Tags for Keys", "Decrypt", "Random".

• Add chapter "Integration"

  • Add "Accessing a NetHSM using the PKCS#11 driver" chapter.
  • Add "Development and Testing" chapter.
  • Update links to new API specification file.

• Add chapter "Guides"

  • Chapter will get additions with following PRs.

• Various bug fixes.