Fix install help documentation

[SergioGasquez]

• Improved esp-idf-version documentation
• Improved profile-minimal documentation
• Improved export-file documentation
• Update usage sections of Readme
• If you provide a wrong path for export-file argument, the following error will prompt:

esp@7f6b5a7b7dc9:~/espup$ cargo r -r -- install -f some_directory/
   Compiling espup v0.2.5-dev (/home/esp/espup)
    Finished release [optimized] target(s) in 54.01s
     Running `target/release/espup install -f some_directory/`
[2022-12-29T13:09:51Z INFO ] 💽  Installing esp-rs
Error: espup::wrong_export_file

  × ⛔  Wrong export file destination: 'some_directory/'. Please, use an absolte or releative path (including the file and its extension).

See #121 for more details