Add support for lcd_i2c extension to use floats in showNumber and showNumberAtPos

[Pascal-Flores]

Title.

At the moment the bottleneck comes from block definition, which only takes as input an int for these methods.

What to do :

Create a ts file for these two methods, define the blocks in this file, convert the number typed parameter into a string, and then call the C++ methods showString and showStringAtPos.