Add colors to data types

[alexanderzeillinger]

Is your feature request related to a problem? Please describe.
I am coming from SqlDBM and I am used to having colors for each data type.

Describe the solution you'd like
I suggest coloring the data types to make them more distinguishable.

Additional context
Below are before and after screenshots.
Bonus: I also prefer a monospace font to better see the actual length of a column name.
Bonus: I replaced the "?" for nullable fields with the word "NULL" which I find more declarative.

[MohabASHRAF-byte]

Can I work on this? @1ilit

[Happy4Game]

I started to work on it, I added colors for the most used data types
I'm trying to make a PR (be gentle, it's my first real issue)