add section on gdal api

[pvgenuchten]

it adds a section on gdal api, which from 3.8/3.11 has good features to get/set metadata at band level

also adds an example of creating a cog from tiff

with a sample to display it, adds localtileserver package, it is quite big, maybe better to look for alternative with geotiff.js...

welcoming your feedback

fixes #233

[pvgenuchten]

Not happy with localtileserver, aim to rewrite sample to use local cog processing

import leafmap.maplibregl as leafmap

m = leafmap.Map(center=[5.12, 52.09], zoom=7)
cog_url = "https://githubusercontent.com"
m.add_cog_layer(url=cog_url, name="Mijn COG Data", colormap_name="terrain")
m