Ledger view - improve the Age filter

[aluccaroni]

The age filter inside the Ledgers page seems to work erratically

The only way that it works correctly is if i put a simple number and it search the ledger older that the specific age. If I try to put anything else it display strange result (for example <1000 to search for ledger newer than 1000 hours).

The default search should be "less than".
We need to support an "equal than" and "more than".
We need to support a "range" search.

For example:

3000  should search <3000
>3000 should search >3000
=3000 should search exact 3000
<5000,>3000 should search the 3000-5000 range