Refactors the bigip_sys_global module (#34438)

Changes include the current f5 coding standards and unit tests
for the module

test/units/modules/network/f5/fixtures/load_sys_global_settings.json

@@ -0,0 +1,24 @@
+{
+    "kind": "tm:sys:global-settings:global-settingsstate",
+    "selfLink": "https://localhost/mgmt/tm/sys/global-settings?ver=13.0.0",
+    "awsApiMaxConcurrency": 1,
+    "consoleInactivityTimeout": 0,
+    "customAddr": "none",
+    "failsafeAction": "go-offline-restart-tm",
+    "fileBlacklistPathPrefix": "{/shared/3dns/} {/shared/bin/} {/shared/core/} {/shared/datasync/} {/shared/em/} {/shared/GeoIP/} {/shared/images/} {/shared/lib/} {/shared/lib64/} {/shared/log/} {/shared/lost+found/} {/shared/mgmt/} {/shared/nfb/} {/shared/ssh/} {/shared/statsd/} {/shared/tmstat/} {/shared/vadc/} {/config/aaa/} {/config/big3d/} {/config/bigip/} {/config/filestore/} {/config/gtm/} {/config/httpd/} {/config/ntp.conf} {/config/rndc.key} {/config/ssh/} {/config/ssl/}",
+    "fileBlacklistReadOnlyPathPrefix": "{/etc/shadow}",
+    "fileLocalPathPrefix": "{/shared/} {/tmp/}",
+    "fileWhitelistPathPrefix": "{/var/local/scf} {/tmp/} {/shared/} {/config/} {/usr/share/aws/}",
+    "guiSecurityBanner": "enabled",
+    "guiSecurityBannerText": "Welcome to the BIG-IP Configuration Utility.\n\nLog in with your username and password using the fields on the left.",
+    "guiSetup": "disabled",
+    "hostAddrMode": "management",
+    "hostname": "bigip1",
+    "lcdDisplay": "enabled",
+    "ledLocator": "disabled",
+    "mgmtDhcp": "enabled",
+    "netReboot": "disabled",
+    "passwordPrompt": "Password",
+    "quietBoot": "enabled",
+    "usernamePrompt": "Username"
+}