Resolve "Get image metadata as dict"

Closes #49 (closed)

The returned app.metadata returns something like:

{
    "AREA_OR_POINT": "Area",
    "DataType": 1.0,
    "DriverLongName": "GeoTIFF",
    "DriverShortName": "GTiff",
    "GeoTransform": [
        760056.0,
        6.0,
        0.0,
        6946092.0,
        0.0,
        -6.0
    ],
    "LowerLeftCorner": [
        760056.0,
        6944268.0
    ],
    "LowerRightCorner": [
        761562.0,
        6944268.0
    ],
    "ProjectionRef": "PROJCS[\"RGF93 v1 / Lambert-93\",\n...AUTHORITY[\"EPSG\",\"2154\"]]",
    "ResolutionFactor": 0,
    "SubDatasetIndex": 0,
    "TIFFTAG_SOFTWARE": "CSinG - 13 SEPTEMBRE 2012",
    "TileHintX": 251.0,
    "TileHintY": 8.0,
    "UpperLeftCorner": [
        760056.0,
        6946092.0
    ],
    "UpperRightCorner": [
        761562.0,
        6946092.0
    ]
}

tests/test_core.py

 import pytest
 
-import pyotb
 from tests_data import *
 
 
@@ -78,7 +77,18 @@ def test_data():
 
 
 def test_metadata():
-    assert INPUT.metadata["Metadata_1"] == "TIFFTAG_SOFTWARE=CSinG - 13 SEPTEMBRE 2012"
+    INPUT2 = pyotb.Input(
+        "https://sentinel-cogs.s3.us-west-2.amazonaws.com/sentinel-s2-l2a-cogs/"
+        "47/Q/RU/2021/12/S2B_47QRU_20211227_0_L2A/B04.tif"
+    )
+    assert "ProjectionRef", "TIFFTAG_SOFTWARE" in INPUT.metadata
+    assert "ProjectionRef", "OVR_RESAMPLING_ALG" in INPUT2.metadata
+
+    # Metadata with numeric values (e.g. TileHintX)
+    fp = "https://gitlab.orfeo-toolbox.org/orfeotoolbox/otb/-/raw/develop/" \
+         "Data/Input/radarsat2/RADARSAT2_ALTONA_300_300_VV.tif?inline=false"
+    app = pyotb.BandMath({"il": [fp], "exp": "im1b1"})
+    assert "TileHintX" in app.metadata
 
 
 def test_nonraster_property():