doorlock: update docs to reflect changes, remove unnecessary requirements

doorlock: remove unnecessary BOSSA and python serial requirements

• delete unnecessary BOSSA and python serial requirements
• replace meta-oniro-blueprint with meta-oniro-blueprints-doorlock because it is a leftover from the blueprint restructuring and migration to EF.

rewrite Setting a pin section

following testing with the latest doorlock version, pressing multiple keys simultaneously simply register each key separately therefore the docs does not reflect the actual functioning. Fixing that.

Relate-to: #2 (closed)

Signed-off-by: Francesco Pham francesco.pham@huawei.com