Allow users to search individual groups and channels

When a user is on a specific group or channel page, and they click to search, there should be two options in the dropdown.

For example, if you search "open source" while browsing Mark's channel, the search drop down should give two options:

• "open source" - Search Minds
• "open source" - Search @mark's channel

This logic should also apply for groups. If you are browsing the Help & Support group, the search options should say:

• "open source" - Search Minds
• "open source" - Search Help & Support group

If you click to Search Minds, we should give the search results as we do now.

If you click to Search an individual group or channel, we should query only the content within that group, and provide search results in the same layout, but only with results specific to that group.