Customize Table Alias for Questions in Graphical Query Editor

**Is your feature request related to a problem? Please describe.**
_A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]_
When using the graphical query editor, sometimes tables have long names that don't match how I want them to display in a column display by default.

[Really Long Table Name --> Column Name]

This is not the best user experience, and makes table readability and editing questions more frustrating.

In addition, sometimes I need to join to the same table multiple times on different keys (e.g. I use a dates table to map dates to our fiscal calendar). If I join on close date and on start date, I'll get

[Dates --> Fiscal Quarter]
[Dates_2 --> Fiscal Quarter]

**Describe the solution you'd like**
A clear and concise description of what you want to happen.
I'd like to set aliases for tables in the graphical query editor, so that instead of:
[Really Long Table Name --> Column Name]
I could display
[RLTN Alias --> Column Name]
and instead of
[Dates --> Fiscal Quarter]
[Dates_2 --> Fiscal Quarter]

I could see
[Close Date-->Fiscal Quarter]
[Start Date-->Fiscal Quarter]

**Describe alternatives you've considered**
A clear and concise description of any alternative solutions or features you've considered.
My best alternative right now is to just use the SQL editor to write this, but I find it much harder to create a quality, interactive reporting experience that way, or to write all of these joins into views on our data warehouse, which duplicates even more code. I can edit the column display names individually, but that's super manual.

**How important is this feature to you?**
Note: the more honest and specific you are here the more we will take you seriously.
I'm not dropping Metabase over this, but this would make my use cases much easier--this is just a point of confusion/manual additional effort that I know is easily handled in SQL, and that I'd hope could be easily addressed in the editor.

**Additional context**
Add any other context or screenshots about the feature request here.

No files, tests, or entry points are named. Start by locating the graphical query editor and its table and column display handling, then trace how repeated joins are represented. Done means users can set table aliases and see those aliases for long names and repeated joins without manually renaming columns.

Written by the indexing model from the issue text.