fix(kuma-cp): concurrent mesh cache map write

[michaelbeaumont]

Advantage over #5252 and the alternative there being that locking is handled by the data structure, the expirationTime time check is handled by the data structure and this eventually cleans up unused meshes.

Closes #5245
Closes #4282

Checklist prior to review

• Link to docs PR or issue --
• Link to UI issue or PR --
• Is the issue worked on linked? --
• The PR does not hardcode values that might break projects that depend on kuma (e.g. "kumahq" as a image registry) --
• The PR will work for both Linux and Windows, system specific functions like syscall.Mkfifo have equivalent implementation on the other OS --
• Unit Tests --
• E2E Tests --
• Manual Universal Tests --
• Manual Kubernetes Tests --
• Do you need to update UPGRADE.md? --
• Does it need to be backported according to the backporting policy? --
• Do you need to explicitly set a > Changelog: entry here or add a ci/ label to run fewer/more tests?

[bartsmykla]

@michaelbeaumont could we merge this PR?

[michaelbeaumont]

Maybe @lobkovilya can take a look again too?