Adding rendering for big natural=bay

[kocio-pl]

Rendering big bay labels is currently missing, notable example is Port Phillip Bay in Australia:

Using Mapnik 3.0.15 (currently in Kosmtik):

z8

z9 (probably eclipsed by a town name)

Mapnik 3.0.19 (latest release):

z8

z9

Related to #2068.

[geozeisig]

Render the label for ocean and sea in the same way as bay in blue letters. For ocean the tag place=ocean is used and for a large sea place=sea. There are not many of them, of course, but it's still important to show them. You could show them from Z4. Most of these objects are mapped as nodes, but we could change that so that they become areas. An example for testing would be Black Sea.

[kocio-pl]

I prefer to not go too fast. Technically it's easy, but each type of water might have some special problems (including node/area and multiple languages in name - Baltic would have 8). Bays are good for testing for some time in my opinion: some of them are similar to lake, some other are like named part of the sea, so it's good to review it after some time and learn from it.

[HolgerJeromin]

ocean and sea is discussed in #2278
See especially this comment #2278 (comment)

[jeisenbe]

I’d like to note that this PR was merged only 2 days after it was opened, with no time for comments, and while it was technicallly approved by @matthijsmelissen there was no discussion of the impact on mappers by encouraging mapping of huge, non-verfiable bay polygons in cases like Hudson Bay or the Bay of Biscay.

Based on our consens-based decision making process, this PR should not have been merged.