Plus (+) signs in DB URL password should be preserved as is

[Rongronggg9]

Describe the bug https://github.com/tortoise/tortoise-orm/blob/76cfc14232fcc8eba8680db4ec293952d14cb1a9/docs/databases.rst?plain=1#L27-L33 https://github.com/tortoise/tortoise-orm/blob/76cfc14232fcc8eba8680db4ec293952d14cb1a9/tortoise/backends/base/config_generator.py#L175

Escaping ` (space) with+is only allowed in query strings (that is to say,+in other parts should stay as is when decoded) and is obsolete. Popular libraries, e.g.,libpqand SQLAlchemy, require (space) to be percent-encoded (%20) and preserve+inusername:passwordas is when decoding. Some PaaS platforms, e.g., [Railway.app](https://railway.app), pass DB URL with plain+` in the password, via environment variables, etc.

To Reproduce N/A

Expected behavior Use urlparse.unquote() instead.

Additional context

• https://datatracker.ietf.org/doc/html/rfc1630
• https://stackoverflow.com/questions/1634271/url-encoding-the-space-character-or-20
• https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNSTRING-URIS
• https://github.com/postgres/postgres/blob/9ba9c7074fa76787530ac0d50313e317ac7032b9/src/interfaces/libpq/fe-connect.c#L6856
• https://github.com/sqlalchemy/sqlalchemy/blob/523285d679fb6b456fd6cfbeeed97644b8cd2ade/lib/sqlalchemy/engine/url.py#L887-L891
• https://github.com/sqlalchemy/sqlalchemy/blob/523285d679fb6b456fd6cfbeeed97644b8cd2ade/lib/sqlalchemy/engine/url.py#L913