FEAT: Improve behavior of search / function on tree

[KevsterAmp]

• Closes [FEAT] Search tables (/) within a specific database #121

Current Behavior

Running the search command / will expand all databases and find all possibilities of tables within the whole server, throughout all databases.

The issue arises when there are multple instances of table names within multiple databases. it becomes hard to determine which database the focused table is from since the database is expanded, and if there are 20+ tables you cannot see the DB name unless you move up. 

Implemented Behavior

To mark a database as "selected" It has to be the currNode and it should be expanded.

• If there is no database selected. The search function will search throughout the names of all the databases ONLY.
• If there is a database selected. The search function will search thorughout the names of all the tables within the selected database.

I believe this is a better implementation since its most common to search a table within a specific database, rather than all the databases.

I can also include in this PR to move the command that "searches on all databases" to CTRL + /.

[KevsterAmp]

Found a bug that I'm not sure how to fix.
When you expand and collapse database node/s, the app seems to record all the tables within it. So when you run a search command even if there are no selected database. It will include the tables within the previously expanded in its search.

At first glance, i think has to be related tree.state.searchFoundNodes. I'll try to look at the issue more later in the day

[KevsterAmp]

Thoughts on this? @jorgerojas26 Thanks

[ccoVeille]

Suggested change

	var searchStartNode *tview.TreeNode
	if currNode != nil && currNode.IsExpanded() {
	// search between tables if theres a curentdatabase selected
	searchStartNode = currNode
	} else {
	// if there's no current database selected, search within the database names only
	searchStartNode = rootNode
	}
	// search within the database names only by default
	searchStartNode := rootNode
	if currNode != nil && currNode.IsExpanded() {
	// search between tables if there is a database selected
	searchStartNode = currNode
	}