Major rewrite

* [x] remove tunneling
* [x] push

    * [x] Change mode into '--what'
    * db

        * [x] add mode support
        * [x] Add better names for dumps to avoid overriding.
        * [x] Add --network flag to 'search-replace' for mulisite compatibility
    * uploads

        * [x] Added '--upload' to select between 'scp' and 'rsync'
        * [x] rsync
* [x] Change prepare_and_extract into a sanitization function
* Documentation

    * [x] Constants on top
    * [x] Each subcommand
    * [x] Subcommands params documentation (push --mode)

* [x] Better help: added manuals
* Constants

    * [x] Manage names and requirement from a static property
        * [x] Supports constant fallback in case it's not set

    * [x] Change name from %ENV%_PATH to %ENV%_SSH_PATH for consistency
    * [x] Fill SSH_DB data from SSH data if missing.