Task/392 service path service path unit tests

### Description
- Unit tests for queryContext
- Initial sanity check of Service Path, with corresponding unit tests

New tests in mongoQueryContext_test.cpp should follow the style of existing test and check every field in the queryContextResponse, e.g.:

```
    /* Check response is as expected */
    EXPECT_EQ(SccOk, ms);

    EXPECT_EQ(0, res.errorCode.code);
    EXPECT_EQ(0, res.errorCode.reasonPhrase.size());
    EXPECT_EQ(0, res.errorCode.details.size());

    ASSERT_EQ(1, res.contextElementResponseVector.size());
    /* Context Element response # 1 */
    EXPECT_EQ("E1", RES_CER(0).entityId.id);
    EXPECT_EQ("T1bis", RES_CER(0).entityId.type);
    EXPECT_EQ("false", RES_CER(0).entityId.isPattern);
    ASSERT_EQ(2, RES_CER(0).contextAttributeVector.size());
    EXPECT_EQ("A1", RES_CER_ATTR(0, 0)->name);
    EXPECT_EQ("TA1", RES_CER_ATTR(0, 0)->type);
    EXPECT_EQ("val1bis", RES_CER_ATTR(0, 0)->value);
    EXPECT_EQ("A1", RES_CER_ATTR(0, 1)->name);
    EXPECT_EQ("TA1bis", RES_CER_ATTR(0, 1)->type);
    EXPECT_EQ("val1bis2", RES_CER_ATTR(0, 1)->value);
    EXPECT_EQ(SccOk, RES_CER_STATUS(0).code);
    EXPECT_EQ("OK", RES_CER_STATUS(0).reasonPhrase);
    EXPECT_EQ(0, RES_CER_STATUS(0).details.size());
    EXPECT_EQ(SccOk, RES_CER_STATUS(0).code);
    EXPECT_EQ("OK", RES_CER_STATUS(0).reasonPhrase);
    EXPECT_EQ(0, RES_CER_STATUS(0).details.size());
```

Maybe you would think that is "exaggerated" ;) but being so strict has save us for many pain in the past.