Adding pip package support.

[Mr-Sunglasses]

Currently, fs_filepicker only supports the conda package manager, but the pip package manager is widely used. Also the addition of setup docs for local environment setup.

What do you think @ReimarBauer, can I start working on this issue also I have many more suggestions for fs_filepicker

[ReimarBauer]

@Mr-Sunglasses great :)

[Mr-Sunglasses]

#19 Related to this issue.

[ReimarBauer]

won't do