Playbook fixes

[nymius]

Description

This PR fixes some of the issues raised by #52:

• On doc/tabconf7 just recipe _init_regtest_sp one of the commands was flagged to use the wrong chain.
• The bdk_sp_cli_v2 package has been merged, and the original branch removed, making this command:

cargo install --git https://github.com/nymius/bdk-sp bdk_sp_cli_v2 --branch docs/workshops --all-features

outdated. This PR changes the command to point to bitcoindevkit/bdk-sp and to the master branch.

Changelog notice

* fix(tabconf7): replaces signet by regtest chain in `_init_regtest_sp` just recipe.
* fix(tabconf7): replaces `nymius/bdk-sp` on `docs/workshops` branch by `bitcoindevkit/bdk-sp` on `master` branch to install `bdk_sp_cli_v2` tool in `_local_install` recipe.

Fixes #52.