Updated parts of the docu and restructured them

[roeslpa]

1. Removed all obsolete information
   • Modified some chapters regarding the current plans and implementation
2. Received information on current implementation of account, identity and contact from @audax
   • Split this information in local and remote stored data
3. Collected all information on the drop protocol (in correspondence see #120 )
   • Merged the information (left out Proof of Work)
4. Marked to be defined and to be reviewed paragraphs
5. Marked not in BETA chapters and paragraphs

Structure is only a draft and discussion proposal.

[roeslpa]

I would suggest a review as following: _data/docs.yml @thechauffeur _docs/Architectural-Overview.md @thechauffeur (needs to be enhanced with the stack description) _docs/Components-Bridgehead.md (Renamed to ..Platform-Interface.md) _docs/Components-Contacts.md any @Qabel/developer _docs/Components-Modules.md any @Qabel/developer _docs/Components-Platform-Interface.md any @Qabel/developer _docs/Qabel-Client-Configuration.md (Converted to Local-Data.md and Remote-Data.md) _docs/Qabel-Client-Contact-Drop-Messages.md (Converted to Local-Data.md and Remote-Data.md) _docs/Qabel-Client-Drop.md (Integrated into Protocol-Drop.md) _docs/Qabel-Client-Local-Data.md @audax _docs/Qabel-Client-Remote-Data.md @audax _docs/Qabel-Protocol-Drop.md @L-Henke or @jasinai _docs/Qabel-Protocol-ProofOfWork.md any @Qabel/developer

Resolves https://github.com/Qabel/qabel-core/issues/438

[audax]

• prefixes in identity
• public key not needed in identity

[audax]

• key format: define.

@jmt85 @L-Henke

[audax]

Remove 'my_identity' : STR in the contact export

[roeslpa]

• prefixes and public key for identity solved
• my_identity was already removed
• new issue #138 for defining the key format (can be integrated afterwards)