README.md: mention which plugins require Limnoria.

[SKIP CI]
ChannelStatus: add Limnoria requirement to README.md.

[SKIP CI]
GitHub: README: mention Limnoria requirement. Closes #197 .

[SKIP CI]
Glob2Chan: mention Limnoria requirement in README.

[SKIP CI]
LimnoriaChan: mention Limnoria requirement in README.md.

[SKIP CI]
WebDoc: mention Limnoria requirement in README.

[SKIP CI]
WebLogs: mention Limnoria requirement in README.

[SKIP CI]
Website: mention that this plugin requires Limnoria in README.

[SKIP CI]
WebStats: merge README & README.txt & call them as README.md

& add Limnoria requirement.

[SKIP CI]