[bash_scripts] add automation scripts for direnv security with gpg

[jweeeezy]

• add gpg to linux_setup
• add script that encrypts recursively all .envrc files with one password of given dir/
• add script that decrypts recursively all .envrc files with one password of given dir/
• add script that recursively removes all .envrc files of given dir/

[jweeeezy]

• add WSL compatible auto deletion of .envrc older than a given time period