Improve docker container rebuild speed

[peleccom]

Title

This pull request improve docker container improve process for development.

Description

Before:

Every change in codebase triggered poetry to install all requirements again since ADD . . and docker cache layer break.

After

New approach it to do installation in two steps

1. Copy dependecy locak files and do poetry isntall to install dependecies. Now only changes in poetry.lock or pyproject.toml
   will trigger poetry to install these dependecies again. In all other cases docker will use cached layer

2. Install package itself with poetry install

Related Issue

This fix the following issue
#1622

Motivation and Context

It improve speed for docker container rebuild

How Has This Been Tested?

Tested locally with the following command

1. docker build -t spotdl .
2. Change any files except poetry.lock pyproject.toml
3. Docker should use cached layer for dependencies installation

Screenshots (if appropriate)

Before the change

After the change

Types of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project
• My change requires a change to the documentation
• I have updated the documentation accordingly
• I have read the CONTRIBUTING document
• I have read the CORE VALUES document
• I have added tests to cover my changes
• All new and existing tests passed