text: Title: Support `times` and `x` suffixes with `WHILE` limit to make it more compatible with `Wait Until Keyword Succeeds`
  Body: **Current Behaviour:**
  Currently, WHILE loop have argument 'limit' which handles both 'timeout' and 'number of times loop to iterate'.
  In most of the Robotframework keywords, timeout functionality supports values without suffix (for example, argument value 300 is equivalent to 300 seconds)
  
  When developers use the limit argument for timeout, they forget the suffix (s, sec, min...), as most of the keywords in RobotFramework supports timeout in seconds without suffix. 
  
  For example, below keywords in Robot Framework supports without suffix, except WHILE loop
  ```
  Sleep   300    # Sleeps for 300 seconds
  Wait Until Keyword Succeeds    300    30    My Keyword    args    # Retries My Keyword for 300 second, every 30 seconds
  WHILE    ${status}==${TRUE}    limit=300    # Loops 300 times. This is conflicting with rest other keyword timeout argument values.
  ```
  
  **Feature Request (Either of Possibility 1 OR Possibility 2):**
  
  **Possibility 1:**
  Can there be a timeout argument in addition to limit argument to support timeout even without suffix. (supports timestring, number or integer)
  This will avoid additional instructions to RobotFramework Developers, that to be careful when providing 'limit' argument to WHILE loop. Below is the feature request example.
  
  Example:
  
  ```
  WHILE    ${status}==${TRUE}    limit=5    # Loops 5 times
  WHILE    ${status}==${TRUE}    timeout=300    # Loops only for 5 minutes or 300 seconds
  ```
  
  _**OR**_
  
  **Possibility 2:**
  Can there be a suffix added to limit, something like 'x' or 'times'  as in 'Wait Until Keyword Succeeds'. Same argument name 'limit' should work for both timeout and number of times. 'timeout' argument name not required in this case.
  
  Example:
  
  ```
  WHILE    ${status}==${TRUE}    limit=5x    # Loops 5 times
  WHILE    ${status}==${TRUE}    limit=10 times    # Loops 10 times
  WHILE    ${status}==${TRUE}    limit=300    # Timeout after 5 minutes or 300 seconds of looping
  WHILE    ${status}==${TRUE}    limit=2m    # Timeout after 2 minutes of looping
  ```
  
  