Introduce MapGrid and MapDatum enums

- Added `MapGrid` enum to define grid types and associated projection methods.
- Added `MapDatum` enum to represent geodetic datums with relevant parameters and calculations.

src/main/java/dev/coph/flightscore/backend/map/MapDatum.java

@@ -0,0 +1,58 @@
+package dev.coph.flightscore.backend.map;
+
+public enum MapDatum {
+    WGS84("World Geodetic System 1984", 6378137.0, 298.257223563, 0.0, 0.0),
+    ETRS89("European Terrestrial Reference System 1989", 6378137.0, 298.257222101, 0.0, 0.0),
+    NAD83("North American Datum 1983", 6378137.0, 298.257222101, 0.0, 0.0),
+    CH1903("Swiss MN03", 6377397.155, 299.1528128, 600000.0, 200000.0),
+    CH1903_PLUS("Swiss MN95", 6377397.155, 299.1528128, 2600000.0, 1200000.0),
+    OGB1936("OSGB 1936 / British National Grid", 6377563.396, 299.3249646, 400000.0, -100000.0),
+    LKS94("Lithuania 1994", 6378137.0, 298.257222101, 500000.0, 0.0),
+    SWEREF99("Swedish Reference Frame 1999", 6378137.0, 298.257222101, 150000.0, 0.0),
+    TWD67("Taiwan Datum 1967", 6378160.0, 298.25, 250000.0, 0.0),
+    TWD97("Taiwan Datum 1997", 6378137.0, 298.257222101, 250000.0, 0.0),
+    AGD1966("Australian Geodetic Datum 1966", 6378160.0, 298.25, 500000.0, 10000000.0),
+    ED50("European Datum 1950", 6378388.0, 297.0, 500000.0, 0.0);
+
+    private final String displayName;
+    private final double semiMajorAxis;
+    private final double inverseFlattening;
+    private final double falseEasting;
+    private final double falseNorthing;
+
+    MapDatum(String displayName, double semiMajorAxis, double inverseFlattening, double falseEasting, double falseNorthing) {
+        this.displayName = displayName;
+        this.semiMajorAxis = semiMajorAxis;
+        this.inverseFlattening = inverseFlattening;
+        this.falseEasting = falseEasting;
+        this.falseNorthing = falseNorthing;
+    }
+
+    public String displayName() {
+        return displayName;
+    }
+
+    public double semiMajorAxis() {
+        return semiMajorAxis;
+    }
+
+    public double inverseFlattening() {
+        return inverseFlattening;
+    }
+
+    public double falseEasting() {
+        return falseEasting;
+    }
+
+    public double falseNorthing() {
+        return falseNorthing;
+    }
+
+    public double flattening() {
+        return 1.0 / inverseFlattening;
+    }
+
+    public double semiMinorAxis() {
+        return semiMajorAxis * (1.0 - flattening());
+    }
+}

src/main/java/dev/coph/flightscore/backend/map/MapGrid.java

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+package dev.coph.flightscore.backend.map;
+
+public enum MapGrid {
+    LAT_LONG("Lat/Long", "Geographic"),
+    UTM("Universal Transverse Mercator", "Transverse Mercator"),
+    SWISS_GRID("Swiss Grid", "Oblique Mercator"),
+    BRITISH_NATIONAL_GRID("British National Grid", "Transverse Mercator"),
+    LITHUANIA_TM("Lithuania TM", "Transverse Mercator"),
+    SWEREF_99_TM("SWEREF 99 TM", "Transverse Mercator"),
+    TWD67_TM2("TWD67 TM2", "Transverse Mercator"),
+    TWD97_TM2("TWD97 TM2", "Transverse Mercator"),
+    BNG_OGB_7("BNG OGB-7", "Transverse Mercator"),
+    BNG_OGB_M("BNG OGB-M", "Transverse Mercator");
+
+    private final String displayName;
+    private final String projectionType;
+
+    MapGrid(String displayName, String projectionType) {
+        this.displayName = displayName;
+        this.projectionType = projectionType;
+    }
+
+    public String displayName() {
+        return displayName;
+    }
+
+    public String projectionType() {
+        return projectionType;
+    }
+}