fix: way surface type storage

[aoles]

Pull Request Checklist

• [x] 1. I have rebased the latest version of the main branch into my feature branch and all conflicts have been resolved.
• [x] 2. I have added information about the change/addition to functionality to the CHANGELOG.md file under the [Unreleased] heading.
• [ ] 3. I have documented my code using JDocs tags.
• [x] 4. I have removed unnecessary commented out code, imports and System.out.println statements.
• [x] 5. I have written JUnit tests for any new methods/classes and ensured that they pass.
• [ ] 6. I have created API tests for any new functionality exposed to the API.
• [ ] 7. If changes/additions are made to the ors-config.json file, I have added these to the ors config documentation along with a short description of what it is for, and documented this in the Pull Request (below).
• [x] 8. I have built graphs with my code of the Heidelberg.osm.gz file and run the api-tests with all test passing
• [ ] 9. I have referenced the Issue Number in the Pull Request (if the changes were from an issue).
• [ ] 10. For new features or changes involving building of graphs, I have tested on a larger dataset (at least Germany), and the graphs build without problems (i.e. no out-of-memory errors).
• [ ] 11. For new features or changes involving the graphbuilding process (i.e. changing encoders, updating the importer etc.), I have generated longer distance routes for the affected profiles with different options (avoid features, max weight etc.) and compared these with the routes of the same parameters and start/end points generated from the current live ORS. If there are differences then the reasoning for these MUST be documented in the pull request.
• [x] 12. I have written in the Pull Request information about the changes made including their intended usage and why the change was needed.
• [ ] 13. For changes touching the API documentation, I have tested that the API playground renders correctly.

Fixes #1779.

Information about the changes

In order to be able to encode surface categories as 4 bit values their number has been reduced to 16 by removing the following ones:

• Woodchips: Not particularly common (0.02%) or relevant for routing on ways, because typical features exhibiting this type of surface are located within playgrouds, parks, etc. Note that this has never been functional because its original value of 16 exceeds the available data type range of 4 bits.
• Cobblestone: the OSM tag surface=cobblestone is quite generic as it is used for both sett and unhewn_cobblestone. As such it is ambiguous, because sett is already classified as "Paving Stones".
• Fine gravel: ambiguous as according to OSM wiki surface=fine_gravel is used somewhat inconsistently. It may be used to specify fine loose gravel (...), but it is also sometimes used as an alias for compacted. Therefore, it seems to make sense to marge it with the more generic category for surface=gravel which has very large meaning range. Used for cases ranging from huge gravel pieces like track ballast used as surface, through small pieces of gravel to compacted surface.

Additionally, the category for surface=earth (0.25%) has been changed from "Ground" to "Dirt", and some less common surface types have been assigned to one of the existing categories. All the changes are summarized in the table below. It lists the top 50 values of way surface tags which have a Wiki entry, with "Special" types of surfaces removed. The values from the change column override those from the current one.

value	count	%	current	change
asphalt	27299245	44.73	Asphalt
unpaved	11398669	18.68	Unpaved
paved	4049616	6.64	Paved
concrete	3360006	5.51	Concrete
paving_stones	3306257	5.42	Paving Stones
ground	3209076	5.26	Ground
gravel	2086265	3.42	Gravel
dirt	1538632	2.52	Dirt
grass	1158016	1.9	Grass
compacted	1027824	1.68	Compacted
sand	520011	0.85	Sand
sett	430232	0.7	Paving Stones
fine_gravel	397460	0.65	Fine Gravel	Gravel
wood	208923	0.34	Wood
concrete:plates	177157	0.29	Concrete
cobblestone	151306	0.25	Cobblestone	Paving Stones
earth	150580	0.25	Ground	Dirt
pebblestone	121603	0.2	Compacted
metal	41043	0.07	Metal
grass_paver	40869	0.07	Grass_Paver
unhewn_cobblestone	31514	0.05		Paving Stones
mud	26101	0.04	Ground
concrete:lanes	26090	0.04	Concrete
rock	21325	0.03		Unpaved
stone	11348	0.02		Unpaved
woodchips	9924	0.02	Woodchips	Unpaved
soil	7045	0.01		Dirt
bricks	6578	0.01		Paving Stones
brick	6563	0.01		Paving Stones
trail	5499	0.01
chipseal	3417	0.01		Asphalt
metal_grid	2618	0
cement	2595	0		Concrete
ice	2209	0	Ice
stepping_stones	1850	0
paving_stones:30	1636	0	Paving Stones
shells	1108	0		Unpaved
rocks	923	0		Unpaved
bitmac	543	0		Asphalt
snow	365	0	Ice
tarmac	272	0		Asphalt
salt	197	0		Unpaved
paving_stones:20	147	0	Paving Stones

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
36.3% Coverage on New Code
12.1% Duplication on New Code

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