[feature request] customize header padding

[dave-doty]

It appears that tabulate wants at least 3 spaces between a column delimiter and the header text (in the opposite direction indicated by colalign):

print(tabulate([["First name", "Last name"], ["John", "Doe"]], 
               headers="firstrow", tablefmt="rounded_outline", colalign=("left", "right")))

╭──────────────┬─────────────╮
│ First name   │   Last name │
├──────────────┼─────────────┤
│ John         │         Doe │
╰──────────────┴─────────────╯

I wish I could customize this, particularly for tables with many columns, and allow, say 1 space of padding instead of 3:

print(tabulate([["First name", "Last name"], ["John", "Doe"]], 
               headers="firstrow", tablefmt="rounded_outline", colalign=("left", "right"),
               min_header_padding=1))

╭────────────┬───────────╮
│ First name │ Last name │
├────────────┼───────────┤
│ John       │       Doe │
╰────────────┴───────────╯

It would make sense even to allow this on both sides of the header entry:

print(tabulate([["First name", "Last name"], ["John", "Doe"]], 
               headers="firstrow", tablefmt="rounded_outline", colalign=("left", "right"),
               min_header_left_padding=0, min_header_right_padding=0))

╭──────────┬─────────╮
│First name│Last name│
├──────────┼─────────┤
│ John     │     Doe │
╰──────────┴─────────╯