Calculator: Move towards a Calculator without any numerical errors

[LucasChollet]

The purpose of this PR is to enhance the calculator, mainly by removing numerical errors.

Current progress:

• [x] Support any number
• [x] Support flawless +, -, *
• [x] Display rounded numbers
• [x] Support /, inv without conversion to double
• [x] Enhance user interaction with rounding

Needed fixes:

• [x] Entering a floating point number is really buggy
• [x] Take care of remaining zeros after the comma
• [x] Unable to enter an integer after clearing while entering a floating point

Closes #14062

[LucasChollet]

@creator1creeper1 Any thought on this?

[creator1creeper1]

Very cool! I feel like the resulting code would be even nicer if we extracted out the idea of "fraction of BigIntegers" into a new class such as BigFraction.

[stale[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions!

[LucasChollet]

I only resolved a simple merge conflict.

[stale[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions!

[MacDue]

Boo :ghost:

[LucasChollet]

Going on a "what if I make 8 small PRs out of this one" crusade

[stale[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions!

[stale[bot]]

This pull request has been closed because it has not had recent activity. Feel free to re-open if you wish to still contribute these changes. Thank you for your contributions!