Improved usage information

[gytic]

I wrote some mini-tutorials about how to get started using lazysql as described in #117

To be more precise i wrote 'tutorials' for:

• Connecting to a DB
• Creating a table (redirect to SQL Editor)
• Execute SQL querys
• Open / View a table
• Filter rows
• Insert rows
• Edit a column

I would love to know what you think about the phrasing, the general style and if you would want me to change.

[jorgerojas26]

I really like this. I'll just take a deeper look tomorrow and come back with suggestions, or maybe a merge.

Thank you for the PR.

[gytic]

PR is ready for review