Feature: Add toolbar environment variables

[nakamuraos]

This PR has the features:

1. Add toolbar environment variables: user can add, edit or remove environment variables

How to use?

• This feature only simple attach one or many command to your command which you typed. For example:

# your environment export HOME=/home/p0wny # your command ls -la # the command after you hit enter export HOME=/home/p0wny;la -la

• You also can add many environment variables. They will be joining by ; (your command will final) after you hit enter.
• The changes are only for HTML, JS, not change your PHP code.

2. Fix key arrow up

• When press key arrow up, the cursor will at begin of input. I added a setTimeout() to move cursor to end of input.

setTimeout(function() { eShellCmdInput.focus(); }, 10); 

3. Fix CSS logo

• Your logo is not show on mobile, so I add it again.

4. A little change

• I just define and replace your code as below:

var $ = function (e) { return document.getElementById(e); }

5. Bonus

• A new scrollbar homogeneities with the background color.

[flozz]

Thank you for your contribution, I will review your PR soon :)

[flozz]

Hello,

Thank you again for contributing to p0wny@shell. Here are some some initial review and remarks about the PR

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1. First, there is too much different things in this PR, that makes it more difficult to review. It is better to make one PR for each change:

   • Click on the page to focus the input,
   • Fix the behavior of the ↑ key,
   • CSS fixes (logo and scroll bar)
   • The Env feature

I cherry-picked the 3 first features of the list above as they were mostly ok → it's on master, please update your branch and resolve conflicts ;)

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2. I am not fan of the $ function shortcut, I think it makes the code harder to read, I prefer explicit code.

3. Be careful of the indentation: the project use 4 spaces and no tabs :)

---

I will continue reviewing the env feature itself after you rebased the PR on the new master :)

[nakamuraos]

Thank @flozz for your review.

Sorry for rules of code. Because this really is first my pull request to contribute on GitHub, so I can haven't experience for this 🗡️

Let me to resolve all this issues

[nakamuraos]

Updated as your comment @flozz:

• Revert $ to document.getElementById for explicit code
• Fix conflict

[nakamuraos]

Have a plan to update env feature better after this merged:

• Save history and env to localStorage

Besides, I always want this script as simple as possible (as a part of p0wny-shell's goals)