Laura.hampton/add default go metrics (#18383)

* create file

* add global variable for shared go metrics

---------

Co-authored-by: Kyle Neale <kyle.neale@datadoghq.com>

datadog_checks_base/datadog_checks/base/checks/openmetrics/v2/metrics.py

@@ -0,0 +1,34 @@
+DEFAULT_GO_METRICS = {
+    'go_gc_duration_seconds': 'go.gc.duration.seconds',
+    'go_goroutines': 'go.goroutines',
+    'go_memstats_buck_hash_sys_bytes': 'go.memstats.buck_hash.sys_bytes',
+    'go_memstats_frees': 'go.memstats.frees',
+    'go_memstats_gc_cpu_fraction': 'go.memstats.gc.cpu_fraction',
+    'go_memstats_gc_sys_bytes': 'go.memstats.gc.sys_bytes',
+    'go_memstats_heap_alloc_bytes': 'go.memstats.heap.alloc_bytes',
+    'go_memstats_heap_idle_bytes': 'go.memstats.heap.idle_bytes',
+    'go_memstats_heap_inuse_bytes': 'go.memstats.heap.inuse_bytes',
+    'go_memstats_heap_objects': 'go.memstats.heap.objects',
+    'go_memstats_heap_released_bytes': 'go.memstats.heap.released_bytes',
+    'go_memstats_heap_sys_bytes': 'go.memstats.heap.sys_bytes',
+    'go_memstats_last_gc_time_seconds': 'go.memstats.last_gc_time.seconds',
+    'go_memstats_lookups': 'go.memstats.lookups',
+    'go_memstats_mallocs': 'go.memstats.mallocs',
+    'go_memstats_mcache_inuse_bytes': 'go.memstats.mcache.inuse_bytes',
+    'go_memstats_mcache_sys_bytes': 'go.memstats.mcache.sys_bytes',
+    'go_memstats_mspan_inuse_bytes': 'go.memstats.mspan.inuse_bytes',
+    'go_memstats_mspan_sys_bytes': 'go.memstats.mspan.sys_bytes',
+    'go_memstats_next_gc_bytes': 'go.memstats.next.gc_bytes',
+    'go_memstats_other_sys_bytes': 'go.memstats.other.sys_bytes',
+    'go_memstats_stack_inuse_bytes': 'go.memstats.stack.inuse_bytes',
+    'go_memstats_stack_sys_bytes': 'go.memstats.stack.sys_bytes',
+    'go_memstats_sys_bytes': 'go.memstats.sys_bytes',
+    'go_threads': 'go.threads',
+    'process_cpu_seconds': 'process.cpu.seconds',
+    'process_max_fds': 'process.max_fds',
+    'process_open_fds': 'process.open_fds',
+    'process_resident_memory_bytes': 'process.resident_memory.bytes',
+    'process_start_time_seconds': 'process.start_time.seconds',
+    'process_virtual_memory_bytes': 'process.virtual_memory.bytes',
+    'process_virtual_memory_max_bytes': 'process.virtual_memory.max_bytes',
+}