Oracle: support arcs

[cportele]

Closes ldproxy/ldproxy#1514.

Note that Oracle WKB differs in two aspects from standard WKB for these geometry types:

1. CIRCULARSTRING, COMPOUNDCURVE, CURVEPOLYGON, MULTICURVE, and MULTISURFACE have a different geometry type code.
2. The embedded geometries do not repeat the endian byte for COMPOUNDCURVE and CURVEPOLYGON.

[cportele]

@azahnen - See the FeatureProviderSql: Do you see a better way to pass the information that a WKB blob is an Oracle WKB blob to the decoder?

[azahnen]

@cportele
I see two options:

1. this instanceof FeatureProviderOracle would at least be more resilient against refactorings.
2. Maybe the cleanest option would be to override getDecoder in FeatureProviderOracle, or to introduce a new method createDecoder that only contains the constructor call and override that.

Otherwise, this looks good to me and can be merged.

[cportele]

@azahnen

Option 1 does not work as it would require that xtraplatform-features depends on xtraplatform-features-oracle. I will have a look into option 2.