Update doxygen groupnames to match cFS naming conventions

[astrogeco]

Description

The doxygen "groupnames" do not have any separators and are difficult to read, see CFEAPIESEntryExit in code snippet below.

cFE/docs/src/cfe_api.dox

Lines 5 to 10 in 2afdbc1

	<LI> \ref CFEAPIESEntryExit
	<UL>
	<LI> #CFE_ES_Main - \copybrief CFE_ES_Main
	<LI> #CFE_ES_ResetCFE - \copybrief CFE_ES_ResetCFE
	</UL>
	<LI> \ref CFEAPIESAppControl

See short discussion in #1670 (comment)

Proposed Solution

Have the group name match the updated directory structure after the modules update, for example

• `CFE_CORE_API_ES_EntryExit, or
• `CFE_ES_EntryExit

Alternatives

Leave names as is but introduce underscores CFE_API_ES_EntryExit.