added stake_amount to a fixed 10k value.

In a combination with a wallet size of 1 billion it should never be able to run out of money avoiding false-positives of some users who just wanted to test a strategy without actually checking how the stake_amount-variable should be used in combination with the strategy-function custom_stake_amount

reason: some strategies demand a custom_stake_amount of 1$ demanding a very large wallet-size (which already was set previously)
Others start with 100% of a slot size and subdivide the base-orders and safety-orders down to finish at 100% of a slot-size and use unlimited stake_amount.

Edited docs to reflect that change too

docs/lookahead-analysis.md

@@ -22,6 +22,9 @@ It also supports the lookahead-analysis of freqai strategies.
 - `--cache` is forced to "none".
 - `--max-open-trades` is forced to be at least equal to the number of pairs.
 - `--dry-run-wallet` is forced to be basically infinite.
+- `--stake-amount` is forced to be 10 k.
+
+Those are set to avoid users accidentally generating false positives.
 
 ## Lookahead-analysis command reference
 

freqtrade/optimize/lookahead_analysis_helpers.py

@@ -136,6 +136,12 @@ class LookaheadAnalysisSubFunctions:
             logger.info('Dry run wallet was not set to 1 billion, pushing it up there '
                         'just to avoid false positives')
             config['dry_run_wallet'] = min_dry_run_wallet
+        # fix stake_amount to 10k.
+        # in a combination with a wallet size of 1 billion it should always be able to trade
+        # no matter if they use custom_stake_amount as a small percentage of wallet size
+        # or fixate custom_stake_amount to a certain value.
+        logger.info('fixing stake_amount to 10.000')
+        config['stake_amount'] = 10000
 
         # enforce cache to be 'none', shift it to 'none' if not already
         # (since the default value is 'day')