Mark network monitor factory functions as private.

[ossama-othman]

Move mptcpd_nm_create(), mptcpd_nm_destroy(), and related notify flags to a new <mptcpd/private/network_monitor.h> header. They are only meant for internal mptcpd use.

[coveralls]

Pull Request Test Coverage Report for Build 2835282728

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
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• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 64.601%

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Totals
Change from base Build 2821836556:	0.0%
Covered Lines:	1376
Relevant Lines:	2130

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💛 - Coveralls